Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Flesh out the cap_test regression test.

Add more regression testing, some of which is expected to fail until we
commit more kernel implementation.

Approved by: re (kib), mentor (rwatson)
Sponsored by: Google Inc