Running the Python test suite with -jN now:
- Display the duration of tests which took longer than 30 seconds
- Display the tests currently running since at least 30 seconds
- Display the tests we are waiting for when the test suite is interrupted
Clenaup also run_test_in_subprocess() code.
Python doesn't display the refcount anymore by default. It only displays it
when -X showrefcount command line option is used, which is not the case here.
regrtest can be run with -X showrefcount, the option is not inherited by child
processes.
Move the code to run tests in multiple processes using threading and subprocess
to a new submodule.
Move also slave_runner() (renamed to run_tests_slave()) and
run_test_in_subprocess() (renamed to run_tests_in_subprocess()) there.
