Vulkan validation failures are happening on ComputeShaderTest on
Linux and Windows with AMD. Suppress for now while the issue is
investigated

Bug: angleproject:5912
Change-Id: If89f7c85bb311a68d6cab85e397112b4178e34d7
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2860044Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>