Issue 727 co broadcast on mixed derived type

[vehre]

coverage on master

Summary of changes

Add unit tests and debugging that issue #727 is fixed.

Rationale for changes

Prove that #727 is fixed in the compiler (gcc > 12.0.0 or gcc > 11.2.1 (or current release/gcc-11 branch).

Additional info and certifications

This pull request (PR) is a:

• Bug fix
• Feature addition
• Other, Please describe: Check fix in compiler

I certify that

• I certify that:
  • I have reviewed and followed the contributing guidelines
  • I will wait at least 24 hours before self-approving the PR to give another
    OpenCoarrays developer a chance to review my proposed code
  • I have not introduced errant white space (no trailing white space or white space errors may
    be introduced)
  • I have added an explanation of what these changes do and why they should be included
  • I have checked to ensure there aren't other open Pull Requests for the same change
  • I have you written new tests for these changes
  • I have successfully tested these changes locally
  • I have commented any non-trivial, non-obvious code changes
  • The commits are logically atomic, self consistent and coherent
  • The commit messages follow best practices
  • Test coverage is maintained or increased after this is merged

Code coverage data

[vehre]

Note this MR is against #745.

[rouson]

LGTM