Make debugging test crash easier

Summary:
This commit is not really related to the other from this PR.
I think it can be helpful anyway, so I backport it.

Backport 4/4 of PR11466 (commit c1e5d40)

Depends on D2315

Test Plan:

./test/functional/test_runner.py

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Subscribers: teamcity, schancel

Differential Revision: https://reviews.bitcoinabc.org/D2316