Hide legacy imagefilters::image using filter-quality

Small diffs in a GM -- due to the dual nature of kMedium (cpu and gpu)
Another reason to stop using it, and switch to the more-explicit
sampling.

Bug: skia:7650
Change-Id: Ie7575071b19778626da7f94804abaaa11861a050
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/370259
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
12 files changed