Remove vestigates of paint's filterquality

Assumes no client still defines/needs SK_SUPPORT_LEGACY_SETFILTERQUALITY

Change-Id: If51f91ca8cad493cb5c03afcfade3838c5d78a35
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/429816
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
3 files changed