minor interpreter cleanups

Bug: skia:
Change-Id: Ic87ce714f7936499c47fa2f1f5217333a568519f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/210068
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
1 file changed