I see some regressions when reference leak hunting with -j './python -j8 -R :'

test test_ast crashed -- Traceback (most recent call last):
  File "/home/meadori/src/cpython/Lib/test/regrtest.py", line 1265, in runtest_inne
r
    huntrleaks)  File "/home/meadori/src/cpython/Lib/test/regrtest.py", line 1381, in dash_R
    indirect_test()
  File "/home/meadori/src/cpython/Lib/test/regrtest.py", line 1261, in <lambda>    test_runner = lambda: support.run_unittest(tests)
  File "/home/meadori/src/cpython/Lib/test/support/__init__.py", line 1683, in run_
unittest
    _run_suite(suite)
  File "/home/meadori/src/cpython/Lib/test/support/__init__.py", line 1649, in _run
_suite
    result = runner.run(suite)
  File "/home/meadori/src/cpython/Lib/test/support/__init__.py", line 1548, in run
    test(result)
  File "/home/meadori/src/cpython/Lib/unittest/suite.py", line 76, in __call__
    return self.run(*args, **kwds)
  File "/home/meadori/src/cpython/Lib/unittest/suite.py", line 114, in run
    test(result)
  File "/home/meadori/src/cpython/Lib/unittest/suite.py", line 76, in __call__
    return self.run(*args, **kwds)
  File "/home/meadori/src/cpython/Lib/unittest/suite.py", line 114, in run
    test(result)
TypeError: 'NoneType' object is not callable