Fix nullptr access when ProcessorOptimizationValidationTest fails

Change-Id: Ifcd25299825b633b6eb26f8471ff8321ec65d267
Reviewed-on: https://skia-review.googlesource.com/108064
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
1 file changed