fix hash randomisation bug (RT#81442)

Since new hashing behavior was introduced in perl-5.17.6, tests are failing during installation of the module.

This is the minimal viable fix for the testsuite.

See https://rt.cpan.org/Public/Bug/Display.html?id=81442 for details.

I would gladly help you to do a release, I believe this dist is well worth bringing back to life.