Various fuzz test runner improvements
Summary:
Backport of core PR18166.
The title has been changed because the CI changes are not ported.
Test Plan:
ninja bitcoin-fuzzers ./test/fuzz/test_runner.py <path_to_corpus>
Reviewers: #bitcoin_abc, PiRK
Reviewed By: PiRK
Differential Revision: https://reviews.bitcoinabc.org/D8276