Add support for matrixCompMult in RP codegen.

This is just a softball. 2 more tests pass.

Change-Id: I61355cb0df39cc7c71b5f25bc9a5052acd4384a3
Bug: skia:13676
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/627916
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
2 files changed