I confirmed the above by changing regrtest as follows in the patch (moving the decorator from load_tests()), and trying both placements of the loadTestsFromModule() line.  One gives the warning and one does not:

    if test_runner is None:
        loader = unittest.TestLoader()
        #tests = loader.loadTestsFromModule(the_module)
        @support.reap_threads
        def test_runner():
            try:
                tests = loader.loadTestsFromModule(the_module)
                support.run_unittest(tests)
            finally:
                support.reap_children()
    test_runner()

This is mostly a suggestion though -- not 100%.