gpu fail: webgl_conformance_tests on ATI Mac

webgl_conformance_tests on ATI GPU on Mac Retina on Mac-10.14.6 is
failing in conformance/ogles/GL/lessThan/lessThan_001_to_008.html

Bug: 1154745
Change-Id: I5365aa119a0ec1fa0914da49c1f4525ab78c53f8
TBR: kbr@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2569922Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
Commit-Queue: Robert Kroeger <rjkroege@chromium.org>
Cr-Commit-Position: refs/heads/master@{#832983}

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

@@ -466,6 +466,7 @@ crbug.com/1108676 [ mac ] conformance/ogles/GL/asin/asin_001_to_006.html [ Retry
 # Mac AMD failures
 crbug.com/642822 [ mac amd ] conformance/rendering/clipping-wide-points.html [ Failure ]
 crbug.com/929009 [ mac amd ] conformance/glsl/misc/shader-with-non-reserved-words.html [ RetryOnFailure ]
+crbug.com/1154745 [ mac amd-0x6821 angle-opengl ] conformance/ogles/GL/lessThan/lessThan_001_to_008.html [ RetryOnFailure ]
 
 # TODO(kbr): uncomment the following expectation after test has
 # been made more robust.