Disable webgl-compressed-texture-etc.html webgl-conformance test on CrOS

The test is failing on CrOS and blocking LKGM updates. This disables it
while we figure out what regressed to allow for LKGM updates.

Bug: 1127052
Change-Id: Ie44baff4b78e495c1af42b4f01e4b6bb6b16071d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2404749
Commit-Queue: Ben Pastene <bpastene@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Mitsuru Oshima (Slow: gardener) <oshima@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#806261}

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

@@ -717,6 +717,7 @@ crbug.com/957807 [ chromeos ] deqp/data/gles2/shaders/swizzles.html [ Skip ]
 crbug.com/1043953 [ chromeos ] conformance/textures/misc/texture-size-limit.html [ RetryOnFailure ]
 
 crbug.com/1081973 [ chromeos ] conformance/textures/misc/compressed-tex-image.html [ Failure ]
+crbug.com/1127052 [ chromeos ] conformance/extensions/webgl-compressed-texture-etc.html [ Failure ]
 
 # ChromeOS: AMD
 crbug.com/995652 [ chromeos amd ] conformance/uniforms/out-of-bounds-uniform-array-access.html [ Skip ]