Add some debugging when test_hashtab_thrash fails

Disabling DEBUG_THREADS caused this test to fail on the 32-bit build agent.
Adding some debugging to see why it thinks the test is timing out.


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@396528 f38db490-d61c-443f-a65b-d21fe96a405b