Skip a few context_lost gpu integration tests on Nexus 6

In https://chromium-review.googlesource.com/c/chromium/src/+/1788138,
these tests were enabled on Android, however, they seemed to still
fail on Nexus 6.

The failure is due to tab.action_runner.WaitForJavaScriptCondition(
    'window.domAutomationController._loaded') timed out

BUG=609629
TEST=bot
TBR=kbr@chromium.org

Change-Id: I8ec2e1c2a708cca23c960e7a3232e11598a5f5f8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1808584
Commit-Queue: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#697079}

content/test/gpu/gpu_tests/test_expectations/context_lost_expectations.txt

@@ -42,3 +42,6 @@ crbug.com/880078 [ android ] ContextLost_WorkerRAFAfterGPUCrash_OOPD [ Failure ]
 # The Nexus 6 times out on these tests while waiting for the JS to complete
 crbug.com/611906 [ android qualcomm-adreno-(tm)-420 ] ContextLost_WebGLContextLostFromLoseContextExtension [ Failure ]
 crbug.com/611906 [ android qualcomm-adreno-(tm)-420 ] ContextLost_WebGLContextLostFromQuantity [ Failure ]
+crbug.com/609629 [ android qualcomm-adreno-(tm)-420 ] GpuCrash_GPUProcessCrashesExactlyOncePerVisitToAboutGpuCrash [ Skip ]
+crbug.com/609629 [ android qualcomm-adreno-(tm)-420 ] ContextLost_WebGLContextLostFromGPUProcessExit [ Skip ]
+crbug.com/609629 [ android qualcomm-adreno-(tm)-420 ] ContextLost_WebGLContextLostInHiddenTab [ Skip ]