Issue #23694: Fix usage of _Py_open() in the _posixsubprocess module

Don't call _Py_open() from _close_open_fds_safe() because it is call just after
fork(). It's not good to play with locks (the GIL) between fork() and exec().

Use instead _Py_open_noraise() which doesn't touch to the GIL.
1 file changed