This allows for testing falling into various buckets in the gpu
fallbacks.
Change-Id: Ia0c319a6bdd03c5cdece1ce83ab228c1a3a7c46d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/199420
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
