TC: clear the TC_STAT_RUNNING flag when tc forgot to do so

TCs are supposed to exit with the TC_STAT_RUNNING cleared. If it forgot
to do this, do it by ourselves.
TC: fix the thread_delete

The tc thread should delay more time than tid2 in order to let it run
the test. The hard-coded "27" is not enough in some cases.
Merge pull request #213 from grissiom/more-tc

More tc