Improve modulation detection logic in ProcessorOptimizationValidationTest

Bug: skia:
Change-Id: I6896df2f46d530afbda752894a3fc414ade661df
Reviewed-on: https://skia-review.googlesource.com/c/159521
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed