Cleanup yes/no enums in Ganesh

Yes/no enums should have a base type of bool, and kYes should always
be true. Also, there is no need for a "GrEnumToBool()" function, as we
can just use the enum itself directly: e.g. "GrAA(bool)".

Bug: skia:
Change-Id: I7bb3c2983f717f3467fca4ce6b32920d71026894
Reviewed-on: https://skia-review.googlesource.com/74860
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
10 files changed