Message11214

I am not convinced that this fixes it, deadlocks maybe just become much less likely. AFAICT the deadlock in test_logging is not related to fromClass, but to ReentrantLock and (maybe) guava. That's the common factor between these.

- note that Darjus experimental fix leaves fromClass un-threadsafe testwise
- for me test_logging also always passed so far when run individually hundreds of times in a shellscript-loop; it only deadlocks sometimes in context of the testsuit
- to reproduce it in a "convenient" way, run testsuite frequently only up to test_logging, e.g. by adjusting Lib/test/regrtest.py; set tests = tests[:275] in line 377.