Disable flaky tests in ImplicitWaitTest class for Android Chromium

ImplicitWaitTest class tests started to fail on Android Chromium build bot.
Disabling all tests for this class.

Bug: chromedriver:2376
Change-Id: I0691b82fc269b4974d31ffcaabd3251858cd8444
Reviewed-on: https://chromium-review.googlesource.com/1003525Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Artur Khachatryan <khachatryan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549681}

chrome/test/chromedriver/test/test_expectations

@@ -291,6 +291,8 @@ _OS_NEGATIVE_FILTER['android:chromium'] = (
         'MiscTest.testShouldReportTheCurrentUrlCorrectly',
         'MiscTest.testStimulatesStrangeOnloadInteractionInFirefox',
         'ElementAttributeTest.testShouldCorrectlyReportValueOfColspan',
+        # https://bugs.chromium.org/p/chromedriver/issues/detail?id=2376
+        'ImplicitWaitTest.*',
     ]
 )
 _OS_NEGATIVE_FILTER['android:chrome_beta'] = (