These aren't allowed in GLSL, and typically don't make sense.
Change-Id: I0afca0df638590466922a809e91ef0be35b13ca8
Bug: skia:10765
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/324816
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
