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: Remove comment that the comma operator is missing in arithmetic
expansion.

The comma operator is not listed in POSIX.1-2008 XCU 1.1.2.1 Arithmetic
Precision and Operations (referenced by XCU 2.6.4 Arithmetic Expansion) and
is therefore not required.

sh: arith: Test an octal constant as well.

sh: Add a regression test that tries out all arithmetic ops.

MFC after: 1 week