Apply clang-tidy suggestion to GrProcessorUnitTest.cpp

Change-Id: I9892a76e55b6323504f3bf1f6477c581938d95d1
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/946636
Commit-Queue: Nicolette Prevost <nicolettep@google.com>
Reviewed-by: Nicolette Prevost <nicolettep@google.com>
Auto-Submit: Kaylee Lubick <kjlubick@google.com>
1 file changed