gpu: Reenable now-passing test on SkiaRenderer Vulkan Android

Pixel_WebGLCopyImage is passing again on tip of tree. Reenabling it.

TBR=kbr@chromium.org

Bug: 1037654
Change-Id: Ic24f74191fa063adb307363dd4c672ba98720ce4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1999156Reviewed-by: Khushal <khushalsagar@chromium.org>
Commit-Queue: Khushal <khushalsagar@chromium.org>
Commit-Queue: Nathan Zabriskie <nazabris@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#731676}

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

@@ -239,5 +239,3 @@ crbug.com/1028975 [ win ] Pixel_PrecisionRoundedCorner [ RetryOnFailure ]
 
 # VP9 appears to not recover correctly after GPU process crashes on Windows.
 crbug.com/1033982 [ win nvidia ] Pixel_Video_Context_Loss_VP9 [ RetryOnFailure ]
-
-crbug.com/1037654 [ use-vulkan android android-chromium skia-renderer ] Pixel_WebGLCopyImage [ Failure ]