[graphite] Enable LCD blending

Change-Id: I17c7c842c17cb4b3227604275c1d02bab55e0a4f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/744137
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: James Godfrey-Kittle <jamesgk@google.com>
22 files changed