Unsuppress sync-webgl-specific.html.

With the WebGL conformance roll in
https://crrev.com/d5fd79c66c041e669cb7cc0d0a41dbcdac886649 , this test should
be passing reliably.

Tbr: kainino@chromium.org
Bug: 818336
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I3fbff79ce0cd11afc562870dd4f05ed06303bafd
Reviewed-on: https://chromium-review.googlesource.com/1011593Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550498}

content/test/gpu/gpu_tests/webgl2_conformance_expectations.py

@@ -92,8 +92,6 @@ class WebGL2ConformanceExpectations(WebGLConformanceExpectations):
         'texturelodoffset.html',
         bug=794335)
 
-    self.Fail('conformance2/sync/sync-webgl-specific.html',
-        ['mac', 'win'], bug=818336)
     self.Fail('conformance2/textures/misc/copy-texture-image-same-texture.html',
         ['mac', 'linux'], bug=809233)
     self.Fail('conformance2/textures/misc/copy-texture-image-same-texture.html',