test: Add diamond-shape prioritisetransaction test

Summary:
Backport of core#24623 and core#24637 for the wallet tooling.

The diamond test is not really testing the same thing as the source material because we don't track the fees including ancestors/descendants anymore, but it demonstrates that the *_transfer_multi functions are working.

Depends on D16412.

Test Plan:

./test/functional/test_runner.py mining_prioritisetransaction

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D16413