Skip RedefineBufferInUse Vulkan test on Win/Intel. Also cleans up GenerateWorkarounds a bit for D3D11. BUG=angleproject:2221 Change-Id: I01667f850051045006d3439406aac3f4d094a374 Reviewed-on: https://chromium-review.googlesource.com/754915 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>