BluetoothInternalsTest.Startup_BluetoothInternals is flaky on debug bots.

https://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=BluetoothInternalsTest.Startup_BluetoothInternals

[23653:23653:0403/024651.737969:INFO:CONSOLE(1221)] "Running TestCase BluetoothInternalsTest.Startup_BluetoothInternals", source: test_api.js (1221)
[23653:23653:0403/024659.375779:ERROR:web_ui_test_handler.cc(76)] Failed: RUN_TEST_F("BluetoothInternalsTest","Startup_BluetoothInternals")
AssertionError: expected true to be false
    at Function.assert.isFalse (chai.js:2459:31)
    at assertFalse (test_api.js:863:17)
    at test_api.js:1020:20
    at bluetooth_internals_browsertest.js:675:9
    at <anonymous>Failed: RUN_TEST_F("BluetoothInternalsTest","Startup_BluetoothInternals")
AssertionError: expected 1 to equal 0
    at Function.assert.strictEqual (chai.js:2277:32)
    at assertEquals (test_api.js:893:17)
    at test_api.js:1020:20
    at bluetooth_internals_browsertest.js:603:11Failed: RUN_TEST_F("BluetoothInternalsTest","Startup_BluetoothInternals")
AssertionError: expected true to be false
    at Function.assert.isFalse (chai.js:2459:31)
    at assertFalse (test_api.js:863:17)
    at test_api.js:1020:20
    at bluetooth_internals_browsertest.js:604:11
gen/chrome/test/data/webui/bluetooth_internals_browsertest-gen.cc:35: Failure
Value of: RunJavascriptTestF( true, "BluetoothInternalsTest", "Startup_BluetoothInternals")
  Actual: false
Expected: true
[23653:23653:0403/024659.722347:WARNING:url_request_context_getter.cc(43)] URLRequestContextGetter leaking due to no owning thread.
[  FAILED  ] BluetoothInternalsTest.Startup_BluetoothInternals, where TypeParam =  and GetParam() =  (14942 ms)