drop sub_y == 0 optimization

In my local testing this doesn't seem to make a difference.

Change-Id: Ifcedd94acddb1e20fc3ec0296bb0398ad5341f41
Reviewed-on: https://skia-review.googlesource.com/c/170761
Commit-Queue: Mike Klein <mtklein@google.com>
Commit-Queue: Herb Derby <herb@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
1 file changed