``clean.sh`` scripts have been replaced by lists of expected artifacts for each system test module. The list is defined using the custom ``pytest.mark.extra_artifacts`` mark, which can use both filenames and globs.
Closes #4261
Backport of MR !9426
Merge branch 'backport-4261-add-pytest-fixture-checking-test-artifacts-9.18' into 'bind-9.18'
See merge request isc-projects/bind9!9735