Suppress depth-renderbuffer-initialization.html on AMD GPU on Windows

The test
conformance/renderbuffers/depth-renderbuffer-initialization.html is
flaky on AMD GPU on Windows:

https://ci.chromium.org/p/chromium/builders/try/win-angle-rel-32/3210
https://ci.chromium.org/p/chromium/builders/try/win-angle-rel-32/3155
https://ci.chromium.org/p/chromium/builders/try/win-angle-rel-32/3113

This CL will suppress that test while the issue is investigated.

Bug: 1043773
Tbr: ynovikov@chromium.org
Change-Id: If8b39ea44d0b6c9a78f790c57d2f7897547b7768
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2013263
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733996}

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

@@ -202,8 +202,9 @@ crbug.com/690248 [ win7 nvidia d3d9 ] conformance/canvas/canvas-test.html [ Retr
 # Mark as Fail since it often flakes in all 3 retries
 crbug.com/653533 [ win amd-0x6613 no-passthrough ] conformance/extensions/oes-texture-half-float.html [ Failure ]
 
-# Win / AMD D3D11 failures
+# Win / AMD D3D11 (default) failures
 crbug.com/878780 [ win amd ] conformance/textures/webgl_canvas/* [ RetryOnFailure ]
+crbug.com/1043773 [ win amd ] conformance/renderbuffers/depth-renderbuffer-initialization.html [ RetryOnFailure ]
 
 # Win / AMD D3D9 failures
 crbug.com/475095 [ win amd d3d9 ] conformance/extensions/angle-instanced-arrays.html [ Failure ]