MFC r289446:

Integrate tools/regression/acltools into the FreeBSD test suite as tests/sys/acl

• Make the requirements more complete for the testcases
• Detect prerequisites so the tests won't fail (zfs.ko is loaded, zpool(1) is available, ACL support is enabled with UFS, etc).
• Work with temporary files/directories/mountpoints that work with atf/kyua
• Limit the testcases to work on temporary filesystems to reduce tainting the test host

Reviewed by: trasz (earlier version)
Differential Revision: https://reviews.freebsd.org/D3810