Suppress failing WebGL test on Intel/Windows

This failure is caused with a change in ANGLE that makes sure precisions
are retained on uniform variables.

Bug: angleproject:6228
Change-Id: Ie5f63581a97b7aab360ea4fa69964ac1f99735cd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3077062
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#909575}

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

@@ -225,6 +225,8 @@ crbug.com/angleproject/4931 [ win nvidia angle-vulkan passthrough ] conformance/
 # Win / Intel / Vulkan / Passthrough command decoder
 # Technically flaky, but flake rate is too high for RetryOnFailure.
 crbug.com/angleproject/4922 [ win intel angle-vulkan passthrough ] conformance/context/context-attributes-alpha-depth-stencil-antialias.html [ Failure ]
+# Bug where RelaxedPrecision applied to normalize() produces 0
+crbug.com/angleproject/6228 [ win intel angle-vulkan passthrough ] conformance/misc/shader-precision-format.html [ Failure ]
 
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 # Fuchsia failures #