The test timed out on a CL with only tester config changes.

See https://ci.chromium.org/p/chromium/builders/luci.chromium.try/mac_chromium_rel_ng/144616.

======================================================================
ERROR: testSwitchToFrame (__main__.ChromeDriverTest)
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Traceback (most recent call last):
  File "../../chrome/test/chromedriver/test/run_py_tests.py", line 409, in setUp
    self._driver = self.CreateDriver()
  File "../../chrome/test/chromedriver/test/run_py_tests.py", line 331, in CreateDriver
    **kwargs)
  File "/b/s/w/ir/chrome/test/chromedriver/test/../client/chromedriver.py", line 241, in __init__
    response = self._ExecuteCommand(Command.NEW_SESSION, params)
  File "/b/s/w/ir/chrome/test/chromedriver/test/../client/chromedriver.py", line 292, in _ExecuteCommand
    response = self._executor.Execute(command, params)
  File "/b/s/w/ir/chrome/test/chromedriver/test/../client/command_executor.py", line 201, in Execute
    response = self._http_client.getresponse()
  File "/b/s/w/ir/.swarming_module/lib/python2.7/httplib.py", line 1121, in getresponse
    response.begin()
  File "/b/s/w/ir/.swarming_module/lib/python2.7/httplib.py", line 438, in begin
    version, status, reason = self._read_status()
  File "/b/s/w/ir/.swarming_module/lib/python2.7/httplib.py", line 394, in _read_status
    line = self.fp.readline(_MAXLINE + 1)
  File "/b/s/w/ir/.swarming_module/lib/python2.7/socket.py", line 480, in readline
    data = self._sock.recv(self._rbufsize)
timeout: timed out