Our test runner would sometimes fail at listing instrumentation tests through device.

Example log from: https://chromium-swarm.appspot.com/task?id=37e076893052b510&refresh=10&show_raw=1
I   56.522s TimeoutThread-1-for-list_tests(0384884f0ae5848c)  [host]> /b/swarming/w/ir/third_party/android_tools/sdk/platform-tools/adb -s 0384884f0ae5848c pull /storage/emulated/legacy/temp_file-b71e40fa1846.json /b/swarming/w/itfg4qKF/tmpTm5jMG/list_tests.json
C   56.585s list_tests(0384884f0ae5848c)  (TimeoutThread-1-for-list_tests(0384884f0ae5848c)) Exception on PullFile(0384884f0ae5848c, /storage/emulated/legacy/temp_file-b71e40fa1846.json, /b/swarming/w/itfg4qKF/tmpTm5jMG/list_tests.json, retries=2, timeout=30), attempt 1 of 3: AdbCommandFailedError("(device: 0384884f0ae5848c) adb pull /storage/emulated/legacy/temp_file-b71e40fa1846.json /b/swarming/w/itfg4qKF/tmpTm5jMG/list_tests.json: failed with exit status 1 and output:\n- adb: error: remote object '/storage/emulated/legacy/temp_file-b71e40fa1846.json' does not exist\n",)
I   56.586s TimeoutThread-2-for-list_tests(0384884f0ae5848c)  [host]> /b/swarming/w/ir/third_party/android_tools/sdk/platform-tools/adb -s 0384884f0ae5848c pull /storage/emulated/legacy/temp_file-b71e40fa1846.json /b/swarming/w/itfg4qKF/tmpTm5jMG/list_tests.json
C   56.649s list_tests(0384884f0ae5848c)  (TimeoutThread-2-for-list_tests(0384884f0ae5848c)) Exception on PullFile(0384884f0ae5848c, /storage/emulated/legacy/temp_file-b71e40fa1846.json, /b/swarming/w/itfg4qKF/tmpTm5jMG/list_tests.json, retries=2, timeout=30), attempt 2 of 3: AdbCommandFailedError("(device: 0384884f0ae5848c) adb pull /storage/emulated/legacy/temp_file-b71e40fa1846.json /b/swarming/w/itfg4qKF/tmpTm5jMG/list_tests.json: failed with exit status 1 and output:\n- adb: error: remote object '/storage/emulated/legacy/temp_file-b71e40fa1846.json' does not exist\n",)
I   56.649s TimeoutThread-3-for-list_tests(0384884f0ae5848c)  [host]> /b/swarming/w/ir/third_party/android_tools/sdk/platform-tools/adb -s 0384884f0ae5848c pull /storage/emulated/legacy/temp_file-b71e40fa1846.json /b/swarming/w/itfg4qKF/tmpTm5jMG/list_tests.json
I   56.713s TimeoutThread-1-for-delete_temporary_file(0384884f0ae5848c)  [host]> /b/swarming/w/ir/third_party/android_tools/sdk/platform-tools/adb -s 0384884f0ae5848c shell 'rm -f /storage/emulated/legacy/temp_file-b71e40fa1846.json'
I   56.721s TimeoutThread-1-for-individual_device_tear_down(0384884f0ae5848c)  [host]> /b/swarming/w/ir/third_party/android_tools/sdk/platform-tools/adb -s 0384884f0ae5848c shell '( rm -f /data/local/tmp/chrome-command-line );echo %$?'
I   56.785s TimeoutThread-1-for-individual_device_tear_down(0384884f0ae5848c)  [host]> /b/swarming/w/ir/third_party/android_tools/sdk/platform-tools/adb -s 0384884f0ae5848c shell '( test -e /data/local/tmp/chrome-command-line );echo %$?'
I   56.848s individual_device_tear_down(0384884f0ae5848c)  Flags now set on the device: []
I   56.849s TimeoutThread-1-for-individual_device_tear_down(0384884f0ae5848c)  [host]> /b/swarming/w/ir/third_party/android_tools/sdk/platform-tools/adb -s 0384884f0ae5848c shell '( am clear-debug-app );echo %$?'
I   57.481s TimeoutThread-1-for-individual_device_tear_down(0384884f0ae5848c)  [host]> /b/swarming/w/ir/third_party/android_tools/sdk/platform-tools/adb -s 0384884f0ae5848c shell '( rm -f /data/local/tmp/chrome_timeout_scale );echo %$?'
I   57.556s tear_down_device(0384884f0ae5848c)  Wrote device cache: /b/swarming/w/ir/out/Release/device_cache_0384884f0ae5848c.json
I   57.679s Main  Opening text logdog stream, unified_logcats
I   57.679s Main  Getting logdog client.
C   57.687s Main  Logcat: https://luci-logdog.appspot.com/v/?s=chromium%2Fandroid%2Fswarming%2Flogcats%2F37e076893052b511%2F%2B%2Funified_logcats
E   57.688s Main  Error occurred.
Traceback (most recent call last):
  File "/b/swarming/w/ir/build/android/test_runner.py", line 983, in main
    return RunTestsCommand(args)
  File "/b/swarming/w/ir/build/android/test_runner.py", line 727, in RunTestsCommand
    return RunTestsInPlatformMode(args)
  File "/b/swarming/w/ir/build/android/test_runner.py", line 847, in RunTestsInPlatformMode
    raw_results = test_run.RunTests()
  File "/b/swarming/w/ir/build/android/pylib/local/device/local_device_test_run.py", line 79, in RunTests
    tests = self._GetTests()
  File "/b/swarming/w/ir/build/android/pylib/local/device/local_device_instrumentation_test_run.py", line 317, in _GetTests
    raw_tests = self._GetTestsFromRunner()
  File "/b/swarming/w/ir/build/android/pylib/local/device/local_device_instrumentation_test_run.py", line 595, in _GetTestsFromRunner
    raw_test_lists = self._env.parallel_devices.pMap(list_tests).pGet(None)
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/utils/parallelizer.py", line 263, in pMap
    r.pFinish(None)
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/utils/parallelizer.py", line 135, in pFinish
    self._objs.JoinAll()
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/utils/reraiser_thread.py", line 186, in JoinAll
    self._JoinAll(watcher, timeout)
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/utils/reraiser_thread.py", line 158, in _JoinAll
    thread.ReraiseIfException()
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/utils/reraiser_thread.py", line 81, in run
    self._ret = self._func(*self._args, **self._kwargs)
  File "/b/swarming/w/ir/build/android/pylib/local/device/local_device_instrumentation_test_run.py", line 591, in list_tests
    dev.PullFile(dev_test_list_json.name, host_file)
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/android/decorators.py", line 57, in timeout_retry_wrapper
    retry_if_func=retry_if_func)
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/utils/timeout_retry.py", line 159, in Run
    error_log_func=error_log_func)
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/utils/reraiser_thread.py", line 186, in JoinAll
    self._JoinAll(watcher, timeout)
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/utils/reraiser_thread.py", line 158, in _JoinAll
    thread.ReraiseIfException()
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/utils/reraiser_thread.py", line 81, in run
    self._ret = self._func(*self._args, **self._kwargs)
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/utils/timeout_retry.py", line 152, in <lambda>
    child_thread = reraiser_thread.ReraiserThread(lambda: func(*args, **kwargs),
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/android/decorators.py", line 47, in impl
    return f(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/android/device_utils.py", line 1704, in PullFile
    self.adb.Pull(device_path, host_path)
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/android/sdk/adb_wrapper.py", line 458, in Pull
    self._RunDeviceAdbCmd(cmd, timeout, retries)
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/android/sdk/adb_wrapper.py", line 286, in _RunDeviceAdbCmd
    check_error=check_error)
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/android/decorators.py", line 51, in timeout_retry_wrapper
    return impl()
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/android/decorators.py", line 47, in impl
    return f(*args, **kwargs)
  File "/b/swarming/w/ir/third_party/catapult/devil/devil/android/sdk/adb_wrapper.py", line 266, in _RunAdbCmd
    args, output, status, device_serial)
AdbCommandFailedError: (device: 0384884f0ae5848c) adb pull /storage/emulated/legacy/temp_file-b71e40fa1846.json /b/swarming/w/itfg4qKF/tmpTm5jMG/list_tests.json: failed with exit status 1 and output:
- adb: error: remote object '/storage/emulated/legacy/temp_file-b71e40fa1846.json' does not exist

Logcat:
Device(0384884f0ae5848c) 08-09 15:38:42.679  5651  5651 I MonitoringInstrumentation: Instrumentation Started!
Device(0384884f0ae5848c) 08-09 15:38:42.679  5651  5651 I MonitoringInstrumentation: Setting context classloader to 'dalvik.system.PathClassLoader[DexPathList[[zip file "/system/framework/android.test.runner.jar", zip file "/data/app/org.chromium.chrome.tests-1.apk", zip file "/data/data/org.chromium.chrome/code_cache/test-multidex/code_cache/secondary-dexes/org.chromium.chrome.tests-1.apk.classes2.zip", zip file "/data/app/org.chromium.chrome-1.apk"],nativeLibraryDirectories=[/data/app-lib/org.chromium.chrome.tests-1, /data/app-lib/org.chromium.chrome-1, /vendor/lib, /system/lib]]]', Original: 'dalvik.system.PathClassLoader[DexPathList[[zip file "/system/framework/android.test.runner.jar", zip file "/data/app/org.chromium.chrome.tests-1.apk", zip file "/data/data/org.chromium.chrome/code_cache/test-multidex/code_cache/secondary-dexes/org.chromium.chrome.tests-1.apk.classes2.zip", zip file "/data/app/org.chromium.chrome-1.apk"],nativeLibraryDirectories=[/data/app-lib/org.chromium.chrome.tests-1, /data/app-lib/org.chromium.chrome-1, /vendor/lib, /system/lib]]]'
Device(0384884f0ae5848c) 08-09 15:38:42.679  5651  5651 I MonitoringInstrumentation: No JSBridge.
....
Device(0384884f0ae5848c) 08-09 15:38:47.449  5651  5669 I TestRunner: started: testPlayMp3(org.chromium.chrome.browser.AudioTest)
Device(0384884f0ae5848c) 08-09 15:38:47.449  5651  5651 I MonitoringInstrumentation: Activities that are still in CREATED to STOPPED: 0
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5669 I TestRunner: finished: testPlayMp3(org.chromium.chrome.browser.AudioTest)
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5651 I MonitoringInstrumentation: Activities that are still in CREATED to STOPPED: 0
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5669 I TestRunner: started: testDefaultNoLaunch(org.chromium.chrome.browser.BackgroundSyncLauncherTest)
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5651 I MonitoringInstrumentation: Activities that are still in CREATED to STOPPED: 0
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5669 I TestRunner: finished: testDefaultNoLaunch(org.chromium.chrome.browser.BackgroundSyncLauncherTest)
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5651 I MonitoringInstrumentation: Activities that are still in CREATED to STOPPED: 0
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5669 I TestRunner: started: testHasInstance(org.chromium.chrome.browser.BackgroundSyncLauncherTest)
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5651 I MonitoringInstrumentation: Activities that are still in CREATED to STOPPED: 0
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5669 I TestRunner: finished: testHasInstance(org.chromium.chrome.browser.BackgroundSyncLauncherTest)
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5651 I MonitoringInstrumentation: Activities that are still in CREATED to STOPPED: 0
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5669 I TestRunner: started: testSetLaunchWhenNextOnline(org.chromium.chrome.browser.BackgroundSyncLauncherTest)
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5651 I MonitoringInstrumentation: Activities that are still in CREATED to STOPPED: 0
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5669 I TestRunner: finished: testSetLaunchWhenNextOnline(org.chromium.chrome.browser.BackgroundSyncLauncherTest)
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5651 I MonitoringInstrumentation: Activities that are still in CREATED to STOPPED: 0
Device(0384884f0ae5848c) 08-09 15:38:47.459  5651  5669 I TestRunner: started: testNewLauncherDisablesNextOnline(org.chromium.chrome.browser.BackgroundSyncLauncherTest)
Device(0384884f0ae5848c) 08-09 15:38:47.469  5651  5651 I MonitoringInstrumentation: Activities that are still in CREATED to STOPPED: 0
Device(0384884f0ae5848c) 08-09 15:38:47.469  5651  5669 I TestRunner: finished: 
....