[flang][NFC] Add derived type lowering tests

Add more use cases of lowering of derived types.

This patch is part of the upstreaming effort from fir-dev branch.

Reviewed By: PeteSteinfeld

Differential Revision: https://reviews.llvm.org/D122329



Co-authored-by: Eric Schweitz <eschweitz@nvidia.com>
Co-authored-by: Peter Steinfeld <psteinfeld@nvidia.com>
Co-authored-by: V Donaldson <vdonaldson@nvidia.com>