This will help debug failures on the bots that could be caused by the
wrong test config being used. As a side effect this changes the
condition array of GPUTestConfig to use an angle::BitSetT

BUG=chromium:997351

Change-Id: If742cd3d416694d5df6c3e6c1d722a24f487a960
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1879585
Commit-Queue: Courtney Goeltzenleuchter <courtneygo@google.com>
Reviewed-by: Ian Elliott <ianelliott@google.com>