Copy stable/11@r303970 to releng/11.0 as part of the 11.0-RELEASE
cycle.

Prune svn:mergeinfo from the new branch, and rename it to RC1.

Update __FreeBSD_version.

Use the quarterly branch for the default FreeBSD.conf pkg(8) repo and
the dvd1.iso packages population.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Migrate tools/regression/bin/ tests to the new layout.

This change is a proof of concept on how to easily integrate existing
tests from the tools/regression/ hierarchy into the /usr/tests/ test
suite and on how to adapt them to the new layout for src.

To achieve these goals, this change:

- Moves tests from tools/regression/bin/<tool>/ to bin/<tool>/tests/.
- Renames the previous regress.sh files to legacy_test.sh.
- Adds Makefiles to build and install the tests and all their supporting
data files into /usr/tests/bin/.
- Plugs the legacy_test test programs into the test suite using the new
TAP backend for Kyua (appearing in 0.8) so that the code of the test
programs does not have to change.
- Registers the new directories in the BSD.test.dist mtree file.

Reviewed by: freebsd-testing
Approved by: rpaulo (mentor)

sh: Fix some tests that used sh instead of ${SH}
so they tested the wrong sh.

This was caused because these tests were committed after the sh -> ${SH}
change but were created before.

sh: Do not allow overriding a special builtin with a function.
This is a syntax error.

POSIX does not say explicitly whether defining a function with the same name
as a special builtin is allowed, but it does say that it is impossible to
call such a function.

A special builtin can still be overridden with an alias.

This commit is part of a set of changes that will ensure that when
something looks like a special builtin to the parser, it is one. (Not the
other way around, as it remains possible to call a special builtin named
by a variable or other substitution.)

Exp-run done by: pav (with some other sh(1) changes)