gh-99113: Add Py_MOD_PER_INTERPRETER_GIL_SUPPORTED (gh-104205)

Here we are doing no more than adding the value for Py_mod_multiple_interpreters and using it for stdlib modules.  We will start checking for it in gh-104206 (once PyInterpreterState.ceval.own_gil is added in gh-104204).

Python/Python-ast.c

@@ -12193,6 +12193,7 @@ astmodule_exec(PyObject *m)
 
 static PyModuleDef_Slot astmodule_slots[] = {
     {Py_mod_exec, astmodule_exec},
+    {Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
     {0, NULL}
 };