testing: Check in ref images for Mac ARM debug case (#2083)

We don't test this in CI so it's probably gone undetected for a while,
but there are a few tests that differ slightly for the combination of
ARM-based Mac for debug builds. So check in a few more ref images so
that devs using that platform don't get spurious testsuite failures
for debug builds.

Signed-off-by: Larry Gritz <lg@larrygritz.com>

Author: lgritz