Revert "Suprress failing tests Pixel_WebGL (vulkan_pixel_skia_gold_test)"

This reverts commit 9feadb9f.

Reason for revert: Fix has landed in chrome

Original change's description:
> Suprress failing tests Pixel_WebGL (vulkan_pixel_skia_gold_test)
> 
> Skip failing tests of vulkan_pixel_skia_gold_test:
> Pixel_WebGLGreenTriangle_AA_NoAlpha
> Pixel_WebGLTransparentGreenTriangle_NoAlpha_ImplicitClear
> Pixel_WebGLGreenTriangle_NoAA_NoAlpha
> 
> TBR=bsheedy@chromium.org
> 
> Bug: chromium:1042693
> Change-Id: I9dc03d61a9e28a6b035a33058acff27697f23df0
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2003557
> Reviewed-by: Behdad Bakhshinategh <behdadb@chromium.org>
> Commit-Queue: Behdad Bakhshinategh <behdadb@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#732444}

TBR=bsheedy@chromium.org,behdadb@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: chromium:1042693
Change-Id: I0195d6c320cecacb91420a40fe695235e4a95cac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2012906Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733729}

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

@@ -186,11 +186,6 @@ crbug.com/1008450 [ android skia-renderer ] Pixel_Video_MP4_Rounded_Corner [ Ski
 # Skia Renderer Vulkan (and GL) producing incorrect negative result
 crbug.com/1033113 [ android android-chromium skia-renderer ] Pixel_Video_Context_Loss_VP9 [ Skip ]
 
-# Skia Renderer Vulkan issue with tombstone symbolization
-crbug.com/1042693 [ android android-chromium skia-renderer ] Pixel_WebGLGreenTriangle_AA_NoAlpha [ Skip ]
-crbug.com/1042693 [ android android-chromium skia-renderer ] Pixel_WebGLTransparentGreenTriangle_NoAlpha_ImplicitClear [ Skip ]
-crbug.com/1042693 [ android android-chromium skia-renderer ] Pixel_WebGLGreenTriangle_NoAA_NoAlpha [ Skip ]
-
 # Skia Renderer EGL timeout, fails to load minidump
 crbug.com/1033121 [ android skia-renderer use-gl no-use-vulkan ] Pixel_Video_MP4_FourColors_Aspect_4x3 [ Skip ]
 crbug.com/1033121 [ android skia-renderer use-gl no-use-vulkan ] Pixel_Video_MP4_FourColors_Rot_180 [ Skip ]