Add non-srcover fallback for drawImageSet

Bug: skia:
Change-Id: Ie0b950f0b8bf0986e8419c49594a7b85c42e0295
Reviewed-on: https://skia-review.googlesource.com/c/184921
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
8 files changed