Remove "canCombineOverlappedStencilAndCover"

This looks like a relic from nvpr text.

Bug: skia:8671
Change-Id: I417c7b4565208e3bf91a3891fa59ba50308a8139
Reviewed-on: https://skia-review.googlesource.com/c/183884
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
5 files changed