Disable the coverage-as-alpha optimization flag for the Bicubic effect.

As of http://review.skia.org/303026, the Bicubic effect no longer
modulates by its input color.

Change-Id: I57d0a9fe89271cae3f28b508184190319d863373
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/305783
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
1 file changed