Seeing intermittent failure on this test only on Win7/NVIDIA/D3D11.
Suppress for now.

Bug: angleproject:4163
Change-Id: Idfa44516a194dcd5710622d11801ce089c1e829d
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1931338Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com>
Commit-Queue: Courtney Goeltzenleuchter <courtneygo@google.com>