SimpleStateChangeTestES31.DrawThenSampleWithCompute was failing
since it was introduced.

TBR=syoussefi@chromium.org
Bug: angleproject:5649
Change-Id: I46f531724bd4f12c760675de5038f2345eb21aac
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2692816Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>