Fix data race in :mod:`faulthandler` where concurrent calls to :func:`~faulthandler.dump_traceback_later` and :func:`~faulthandler.cancel_dump_traceback_later` could corrupt the watchdog lock handshake on free-threaded builds.
Fix data race in :mod:`faulthandler` where concurrent calls to :func:`~faulthandler.dump_traceback_later` and :func:`~faulthandler.cancel_dump_traceback_later` could corrupt the watchdog lock handshake on free-threaded builds.