Remove $FreeBSD$: one-line sh pattern

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

Feex a cuple of small typos

- Use LOCALBASE instead of KYUA_PREFIX for the --prefix to kyua(1)
- Use LOCALBASE instead of hardcoding /usr/local for perl

MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D4406 (part of a larger diff)
Reviewed by: emaste, Evan Cramer <eccramer@gmail.com>
Sponsored by: EMC / Isilon Storage Division

As an optimization (in simple, well used cases) only call cat ${.ALLSRC} when
generating files from various sources instead of calling cat ${.ALLSRC} | sed

The perl case was skipped because it's not being used in the tree at this time

Fix atf-sh's integration_test

With the move of atf-sh into /usr/libexec in r267181, some of the
tests in the integration_test program broke because they could not
execute atf-sh from the path any longer.

This slipped through because I do have a local atf installation in
my home directory that appears in my path, hence the tests could
still execute my own version.

Fix this by forcing /usr/libexec to appear at the beginning of the
path when attempting to execute atf-sh.

To make upgrading easy (and to avoid an unnecessary entry in UPDATING),
make integration_test depend on the Makefile so that a rebuild of the
shell script is triggered. This requires a hack in the *.test.mk files
to ensure the Makefile is not treated as a source to the generated
program. Ugly, I know, but I don't have a better way of doing this at
the moment. Will think of one once I address the TODO in the *.test.mk
files that suggests generalizing the file generation functionality.

PR: 191052
Reviewed by: Garrett Cooper

Make bsd.test.mk the only public mk fragment for the building of tests.

Change {atf,plain,tap}.test.mk to be internal implementation details of
bsd.test.mk. Makefiles that build tests should now only include bsd.test.mk
and declaratively specify what they want to build, without worrying about
the internal implementation of the mk files.

The reason for this change is to permit building test programs of different
interfaces from a single directory, which is something I had a need for
while porting tests over from src/tools/regression/.

Additionally, this change makes it possible to perform some other requested
changes to bsd.test.mk in an easier manner. Coming soon.

Support perl-based TAP-compliant test programs.

Introduce a TAP_TESTS_PERL primitive to list test programs written in perl.
Only do this in tap.test.mk because I only expect perl-based test programs
with this interface.

This is very similar to TAP_TESTS_SH but the difference is that we record
in the Kyuafile that the test program requires a perl interpreter. This
in turn makes Kyua mark the test as skipped if the perl package is not yet
installed, instead of mysteriously failing to run the program.

MFC after: 5 days

Add tap.test.mk.

This file provides support to build test programs that comply with the
Test Anything Protocol. Its main goal is to support the painless
integration of existing tests from tools/regression/ into the Kyua-based
test suite.

Approved by: rpaulo (mentor)