6 tests of test.test_regrtest.ProgramsTestCase class introduced in revision 3393d86c3bb2 (in Python >=3.6) fail with --without-threads, because they unconditionally use -j4 option, but -jN where N != 1 is not supported with --without-threads. They also use --timeout option, which is also not supported with --without-threads.

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FAIL: test_module_autotest (test.test_regrtest.ProgramsTestCase)
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Traceback (most recent call last):
  File "/tmp/cpython/Lib/test/test_regrtest.py", line 471, in test_module_autotest
    self.run_tests(args)
  File "/tmp/cpython/Lib/test/test_regrtest.py", line 445, in run_tests
    output = self.run_python(args)
  File "/tmp/cpython/Lib/test/test_regrtest.py", line 417, in run_python
    proc = self.run_command(args, **kw)
  File "/tmp/cpython/Lib/test/test_regrtest.py", line 411, in run_command
    self.fail(msg)
AssertionError: Command ['/tmp/cpython/python', '-X', 'faulthandler', '-I', '-Wd', '-E', '-bb', '-m', 'test.autotest', '-uall', '-rwW', '--timeout', '3600', '-j4', 'test_regrtest_21191_noop19', 'test_regrtest_21191_noop20', 'test_regrtest_21191_noop21', 'test_regrtest_21191_noop22'] failed with exit code 2

stdout:
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Using random seed 5351037
Multiprocess option requires thread support

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stderr:
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Warning: The timeout option requires faulthandler.dump_traceback_later
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