Delete all code related to disabling multisample

Bug: skia:12196
Change-Id: Iae403ae28e134e4762fc7f58bbfe22bf8c42ab97
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/436317
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
29 files changed