Add SK_ASSUME macro, to replace clang-only __builtin_assume

Bug: b/316617002
Change-Id: I3850bfcc63fb4fc5ae02da7282e1d092d6ee8f84
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/793457
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
2 files changed