Skip flaky WebGL test on Win Vulkan Passthrough

conformance/textures/misc/canvas-teximage-after-multiple-drawimages.html

Observed failing on Win Vulkan NVIDIA Passthrough,
but skipping on all Win Vulkan Passthrough as ANGLE doesn't actively
support Win Vulkan Passthrough at the moment.

Bug: angleproject:4334
Change-Id: If8add00e24ec6fdaeaeeb5e4626ffb7de86c483d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2017903Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Auto-Submit: Shahbaz Youssefi <syoussefi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734678}

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

@@ -250,6 +250,7 @@ crbug.com/angleproject/2921 [ win vulkan passthrough ] conformance/uniforms/out-
 crbug.com/angleproject/2899 [ win vulkan passthrough ] WebglExtension_EXT_shader_texture_lod [ Failure ]
 crbug.com/angleproject/3111 [ win vulkan passthrough ] deqp/data/gles2/shaders/swizzles.html [ Skip ]
 crbug.com/angleproject/3741 [ win vulkan passthrough ] conformance/textures/misc/mipmap-fbo.html [ RetryOnFailure ]
+crbug.com/angleproject/4334 [ win vulkan passthrough ] conformance/textures/misc/canvas-teximage-after-multiple-drawimages.html [ Skip ]
 
 # Vulkan / Win / NVIDIA / Passthrough command decoder
 crbug.com/angleproject/3935 [ win nvidia vulkan passthrough ] conformance/canvas/viewport-unchanged-upon-resize.html [ Failure ]