r261081
Replace the old unix_seqpacket and unix_seqpacket_exercise
tests, which were a little broken and not automatable, with
unix_seqpacket_test. It's coverage is a superset of the old
tests and it uses ATF. It includes test cases for bugs
kern/185813 and kern/185812.
r261133
Fix the Makefiles so that the tests I submitted in r261081 will
actually get built.
r261615
tests/sys/Makefile
use TESTS_SUBDIRS for kern instead of SUBDIRS. I don't
think it makes a difference in this case, but
TESTS_SUBDIRS is generally correct for subdirectories
that contain tests.