Fix exit races in test_thread.py and test_threaded_import.py.
I suspect the bug is provokable only under Linux (where child threads
seem to get lots of cycles before they get killed after the main thread
exits), or on multi-processor machines running other OSes.
Bugfix candidate.
When regrtest.py finds an attribute "test_main" in a test it imports,
regrtest runs the test's test_main after the import. test_threaded_import
needs this else the cross-thread import lock prevents it from making
progress. Other tests can use this hack too, but I doubt it will ever be
popular.
ICK ALERT: read the long comment block before run_the_test(). It was
almost impossible to get this to run without instant deadlock, and the
solution here sucks on several counts. If you can dream up a better way,
let me know!
Tim Peters
Jack Jansen