This uncovered a bug in Metal code generation of `matX *= matY` which is
now fixed. (It was emitting the helper function more than once.)
Change-Id: I0aeb0efe7ab5fbf5592a8ca6f4f5b50354d3d7f4
Bug: skia:11262
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/365489
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
