Port paxtest to kyua tests
Now that FreeBSD imported kyua into base, porting paxtest from the tools repo to Kyua would be great. We could more easily track potential regressions. Additionally, we can get rid of the paxtest source tarball in the tools repo.
paxtest lives here: https://git-01.md.hardenedbsd.org/HardenedBSD/tools/src/branch/master/tests/paxtest-freebsd/paxtest-0.9.14-freebsd.tgz