gh-145681: do not deallocate list buffer in _PyList_AsTupleAndClear (GH-145680)

Setting the size to 0 turns the list contents into overallocated memory that the deallocator will free.
Ownership is transferred to the new tuple so no refcount adjustment is needed.

Author: KowalskiThomas

Objects/listobject.c

@@ -3283,10 +3283,8 @@ _PyList_AsTupleAndClear(PyListObject *self)
     Py_BEGIN_CRITICAL_SECTION(self);
     PyObject **items = self->ob_item;
     Py_ssize_t size = Py_SIZE(self);
-    self->ob_item = NULL;
     Py_SET_SIZE(self, 0);
     ret = _PyTuple_FromArraySteal(items, size);
-    free_list_items(items, false);
     Py_END_CRITICAL_SECTION();
     return ret;
 }