Disable some code to handle Metal TSAN errors.

This is a temporary fix until I can figure out where these errors are
coming from.

Bug: skia:9213
Change-Id: Iac21415bf26f39f5237e12ec146769252e833d36
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/223981
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
4 files changed