In the msg and shm tests, if the child exited before the parent
entered sigsuspend(), the test would hang and time out. This was
also a problem in the sem test, but the misuse of atf_tc_pass()
masked it. Adding a short sleep before the sigsuspend() calls made
the hang 100% reliable. With the same sleep in the new version,
the test passes reliably.
Remove calls to atf_tc_pass(). The call in the sem test broke the test
by exiting prematurely, after only one child out of five had finished.
The other two were harmless but unhelpful.
Reduce a one-second sleep to a more reasonable duration so I can quickly
run many iterations of the test.
Re-enable the test in CI.
MFC after: 1 week
Sponsored by: Dell EMC Isilon