Remove SK_SUPPORT_LEGACY_BLURMASKFILTER

Change-Id: I1d99d9bb83d8a612d1c1fd298c1f7ed706a2277b
Reviewed-on: https://skia-review.googlesource.com/118990
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
9 files changed