do/while loops in SPIR-V no longer cause an assertion failure

BUG=skia:

Change-Id: Ic5f590879d8ada5d4580b5c6e9091ccc9532be4b
Reviewed-on: https://skia-review.googlesource.com/6605
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
2 files changed