Suppress WebGL failures with Win/Vulkan/AMD for float canvas tests.

These failures only appear on Win/AMD/Vulkan and are not reproducable locally
yet.

BUG=angleproject:2898
TBR=kbr@chromium.org
NOTRY=true

Change-Id: Ic5024c0de700470ae55e6e17d051322dbc968f17
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1787586Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#693744}

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

@@ -280,6 +280,8 @@ crbug.com/angleproject/2722 [ win nvidia vulkan passthrough ] conformance/render
 crbug.com/angleproject/3883 [ win nvidia vulkan passthrough ] conformance/misc/uninitialized-test.html [ Failure ]
 
 # Vulkan / Win / AMD / Passthrough command decoder
+crbug.com/angleproject/2898 [ win amd vulkan passthrough ] conformance/extensions/oes-texture-float-with-canvas.html [ Failure ]
+crbug.com/angleproject/2898 [ win amd vulkan passthrough ] conformance/extensions/oes-texture-half-float-with-canvas.html [ Failure ]
 crbug.com/angleproject/2722 [ win amd vulkan passthrough ] conformance/rendering/clipping-wide-points.html [ Failure ]
 crbug.com/angleproject/2926 [ win amd vulkan passthrough ] deqp/data/gles2/shaders/conversions.html [ Failure ]
 crbug.com/angleproject/2926 [ win amd vulkan passthrough ] deqp/data/gles2/shaders/linkage.html [ Failure ]