Make configurable the creation of heat stack domain

Heat has graceful fallback code if stack_user_domain is not configured.

It is important that this be configurable, for testing and for those who choose to
not run with a stack_user_domain yet.

Change-Id: I08f017412636327853b3c606afd36ae93aa09288
Fix run_tests to not mask bash8 errors

The addition of the crazy-refs check masked the bash8 exit code.  So add
the same pass/fail handling from exercise.sh to provide a neat summary at
the end of the run.

Change-Id: I169eb90c619a114cf8584bee70b7dcda67769dc5
Merge "Make configurable the creation of heat stack domain"
Merge "Fix run_tests to not mask bash8 errors"