This will cause the test shards to be re-tried due to an invalid
result. The goal is to retry flaky configs where whole shards fail.

Bug: angleproject:6075
Change-Id: I76d0f08da29ffc4bcad7f282f7be38618c384bce
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2982500Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>