try skipping _cvtmask64_u64

This may or may not work.

Change-Id: I0be7517deafe7f27087e782782a7e135110ddebe
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/285683
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>