remove obsolete flag SK_SUPPORT_LEGACY_CANVAS_MATRIX_VIRTUALS

Change-Id: I7f8dabe249a29ffa59e3e6224292895831be13d0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/266196
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
3 files changed