"I enabled faulthandler in subprocesses created by test.regrtest and test.script_helper..."

Oh, it doesn't help for this issue. On Windows, faulthandler is unable to dump the Python traceback on a stack overflow. On UNIX, it allocates a diffrent stack for its signal handler, and so the signal handler can run even on a stack overflow.

The Windows exit code 0xC00000FD (3221225725) means "Stack overflow / exhaustion".

[ 81/375] test_marshal
Traceback (most recent call last):
  File "../lib/test/regrtest.py", line 1618, in <module>
    main_in_temp_cwd()
  File "../lib/test/regrtest.py", line 1593, in main_in_temp_cwd
    main()
  File "../lib/test/regrtest.py", line 775, in main
    raise Exception("Child error on {}: {}".format(test, result[1]))
Exception: Child error on test_marshal: Exit code 3221225725