Exclude a few more tests from mtltestprecompile

These produce slightly different results run to run

Bug: skia:11392
Change-Id: I64adf62132f7432114dcebfad604becf95553be0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/410136
Auto-Submit: Brian Salomon <bsalomon@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
2 files changed