We now catch this error at IR generation time; previously we'd send it
to the driver (where it would fail to compile).
Change-Id: I45890214ffa164be1c0f359320f942bc4dc479ca
Bug: skia:11265
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/365697
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>