Minor style tweaks.

Obtained from:	OpenBSD (CVS rev. 1.7)
MFC after:	3 days
Convert bin/sh/tests to ATF

The new code uses a "test discovery mechanism" to determine
what tests are available for execution

The test shell can be specified via:

  kyua test -v test_suites.FreeBSD.bin.sh.test_shell=/path/to/test/sh

Sponsored by: EMC / Isilon Storage Division
Approved by: jmmv (mentor)
Reviewed by: jilles (maintainer)