Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Drop "All rights reserved" from all my stuff. This includes
Foundation copyrights, approved by emaste@. It does not include
files which carry other people's copyrights; if you're one
of those people, feel free to make similar change.

Reviewed by: emaste, imp, gbe (manpages)
Differential Revision: https://reviews.freebsd.org/D26980

Make test scripts under tests/... non-executable

Executable bits should be set at install time instead of in the repo.
Setting executable bits on files triggers false positives with Phabricator.

MFC after: 2 months

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

MFC after: 2 weeks
Reviewed by: trasz (earlier version)
Differential Revision: https://reviews.freebsd.org/D3810