Remove $FreeBSD$: one-line sh pattern

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

vfs_lookup: Allow PATH_MAX-1 symlinks

Previously, symlinks in FreeBSD were artificially limited to PATH_MAX-2.

Add a short test case to verify the change.

Submitted by: Gaurav Gangalwar <ggangalwar AT isilon.com>
Reviewed by: kib
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D12589

trailing_slash is a TAP-compliant testcase; mark it as such, instead
of calling is a plain testcase.

MFC after: 1 month

Remove WARNS set globally by ../Makefile.inc now

Sponsored by: Dell EMC Isilon

Bump WARNS up to 6 again

Has not been tested (can't be after r312103 without cem's hacks
to atf/kyua)!

Follow-up to r312103:

Revert r310995 as well.

Bump WARNS to 6 to catch simple QA issues like some of the ones I squashed
in r310994

Add basic ATF tests for Capability mode .. lookups

A follow-up to r309887.

Several tests copied verbatim from
https://github.com/emaste/snippets/blob/master/test_openat.c .

Reviewed by: kib@, ngie@ (earlier version)
X-MFC-With: r309887
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D8748

Merge ^/user/ngie/release-pkg-fix-tests to unbreak how test files are installed
after r298107

Summary of changes:

- Replace all instances of FILES/TESTS with ${PACKAGE}FILES. This ensures that
namespacing is kept with FILES appropriately, and that this shouldn't need
to be repeated if the namespace changes -- only the definition of PACKAGE
needs to be changed
- Allow PACKAGE to be overridden by callers instead of forcing it to always be
`tests`. In the event we get to the point where things can be split up
enough in the base system, it would make more sense to group the tests
with the blocks they're a part of, e.g. byacc with byacc-tests, etc
- Remove PACKAGE definitions where possible, i.e. where FILES wasn't used
previously.
- Remove unnecessary TESTSPACKAGE definitions; this has been elided into
bsd.tests.mk
- Remove unnecessary BINDIRs used previously with ${PACKAGE}FILES;
${PACKAGE}FILESDIR is now automatically defined in bsd.test.mk.
- Fix installation of files under data/ subdirectories in lib/libc/tests/hash
and lib/libc/tests/net/getaddrinfo
- Remove unnecessary .include <bsd.own.mk>s (some opportunistic cleanup)

Document the proposed changes in share/examples/tests/tests/... via examples
so it's clear that ${PACKAGES}FILES is the suggested way forward in terms of
replacing FILES. share/mk/bsd.README didn't seem like the appropriate method
of communicating that info.

MFC after: never probably
X-MFC with: r298107
PR: 209114
Relnotes: yes
Tested with: buildworld, installworld, checkworld; buildworld, packageworld
Sponsored by: EMC / Isilon Storage Division

More 'tests' package fixes.

Sponsored by: The FreeBSD Foundation

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

MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division