For test commands, there can be arguments passed to the test binary like `-- --ignored` or `--
--test-threads=1`. For these cases to work properly, the `args` parameter needs to be added to the
end of the 'test' command.
This commit updates the tests to check that this works and also rewrites the
test script from Bash to Perl.
Co-authored-by: Dave Rolsky <autarch@urth.org>
