More flaky failures that were being hidden by test retries. Might take a
few more patches in order to disable test retries.

Bug: angleproject:3271
Bug: angleproject:1729
Change-Id: I97eb02d6e93892a04db8b09992f32c4c20dbd49b
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1549314Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>