MFC r305626,r305629,r307863,r322447,r322448,r322449,r322450,r322451:

r305626 (by oshogbo):

Move libcasper tests from regression/capsicum/libcasper/ to
lib/libcasper/service/${service_name}/tests.

r305629 (by jkim):

Add new directories added in r305626 to fix "make installworld".

r307863 (by emaste):

Set SHLIBDIR before .including src.opts.mk in libcapser services

bsd.own.mk (included from src.opts.mk) sets SHLIBDIR?=${LIBDIR}, so
SHLIBDIR must be set before including either one of them.

MFC with: 305626

r322447:

Fix result printing

- Flushing stdout prevents the buffer from being printed twice, fixing
issues with stdout printing out the testplan, etc, twice.
- Don't print out raw source/line numbers; hide them behind comments.

r322448:

Make root-privileges a requirement for the test

Some of the testcases try to manipulate sysctls that require root privileges,
e.g., "kern.sync_on_panic". Make root-privileges a hard requirement so the
tests don't raise false positives due to privilege issues when calling
sysctlbyname(3) on writable sysctls.

r322449:

Use hardcoded IPv4/IPv6 addresses for google-public-dns-a.google.com instead
of freefall.freebsd.org to unbreak the DNS tests

The address allocations for freefall.freebsd.org have changed in the past 4 years.
Use a more stable set of hardcoded addresses for now to make the tests succeed
reliably.

The hostname should be resolved dynamically instead of hardcoding the addresses in
the future. This is just a bandaid.

r322450:

Integrate the tests moved in r305626 in to the FreeBSD test suite

The reachover Kyuafiles were never added, and thus the tests were installed
as standalone tests, and not integrated into the full suite.

MFC with: r305626, 305629, r307863, r322447, r322448, r322449

r322451:

TESTSDIR isn't required; remove it

MFC with: r322450