Optimize dead-code elimination in SkVM.

By processing the instructions in reverse order, we can avoid the need
for a worklist vector.

Change-Id: Id81673b41ac6f201bac3da87328c9fbdde35846a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/445757
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed