Skip a few context_lost gpu integration tests on Nexus 9

In https://chromium-review.googlesource.com/c/chromium/src/+/1788138,
these tests were enabled on Android. But flakes are seen on Nexus 9:
https://ci.chromium.org/p/chromium/builders/ci/Android%20FYI%20Release%20%28Nexus%209%29/28407

Following the similar pattern of skipping them as in:
https://chromium-review.googlesource.com/c/chromium/src/+/1808584
https://chromium-review.googlesource.com/c/chromium/src/+/1628391

TBR=zmo@chromium.org

Bug: 609629
Change-Id: Ibbdecd58265839c3bf8d2378a0eeba02f1356bf7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2399824Reviewed-by: Shrek Shao <shrekshao@google.com>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Commit-Queue: Shrek Shao <shrekshao@google.com>
Cr-Commit-Position: refs/heads/master@{#805347}

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

@@ -44,6 +44,11 @@ crbug.com/609629 [ android qualcomm-adreno-(tm)-420 ] GpuCrash_GPUProcessCrashes
 crbug.com/609629 [ android qualcomm-adreno-(tm)-420 ] ContextLost_WebGLContextLostFromGPUProcessExit [ Skip ]
 crbug.com/609629 [ android qualcomm-adreno-(tm)-420 ] ContextLost_WebGLContextLostInHiddenTab [ Skip ]
 
+# Flaking on Nexus 9
+crbug.com/609629 [ android nvidia ] ContextLost_WebGLBlockedAfterJSNavigation [ Skip ]
+crbug.com/609629 [ android nvidia ] ContextLost_WebGLUnblockedAfterUserInitiatedReload [ Skip ]
+crbug.com/609629 [ android nvidia ] ContextLost_WebGLContextLostFromGPUProcessExit [ Skip ]
+
 # Mac NVIDIA only uses the low-power GPU.
 crbug.com/681341 [ mac nvidia ] ContextLost_MacWebGLMultisamplingHighPowerSwitchLosesContext [ Skip ]
 crbug.com/681341 [ mac nvidia ] ContextLost_MacWebGLPreserveDBHighPowerSwitchLosesContext [ Skip ]