Mark a WebGL2 CTS flaky

Expand deqp/functional/gles3/shaderindexing/tmp.html Flaky to all Mac AMD

BUG=659871
TBR=kbr@chromium.org

Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: I8825bb13d51449137960331dbfc0fc66de945064
Reviewed-on: https://chromium-review.googlesource.com/580388
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488437}

content/test/gpu/gpu_tests/webgl2_conformance_expectations.py

@@ -557,6 +557,8 @@ class WebGL2ConformanceExpectations(WebGLConformanceExpectations):
         ['mac', 'amd'], bug=636648)
     self.Flaky('deqp/functional/gles3/shaderindexing/mat_02.html',
         ['mac', 'amd'], bug=644360)
+    self.Flaky('deqp/functional/gles3/shaderindexing/tmp.html',
+        ['mac', 'amd'], bug=659871)
 
     # These seem to be provoking intermittent GPU process crashes on
     # the MacBook Pros with AMD GPUs.
@@ -571,10 +573,6 @@ class WebGL2ConformanceExpectations(WebGLConformanceExpectations):
     self.Fail('conformance2/rendering/clipping-wide-points.html',
         ['mac', 'amd'], bug=642822)
 
-    # Mac Pro with AMD GPU
-    self.Flaky('deqp/functional/gles3/shaderindexing/tmp.html',
-        ['mac', ('amd', 0x679e)], bug=659871)
-
     # Mac Intel
     self.Fail('conformance2/rendering/framebuffer-texture-level1.html',
         ['mac', 'intel'], bug=680278)