dict: Fix refleak (GH-31650)

Author: methane

Objects/dictobject.c

@@ -1523,12 +1523,16 @@ dictresize(PyDictObject *mp, uint8_t log2_newsize, int unicode)
 
         // We can not use free_keys_object here because key's reference
         // are moved already.
-        if (oldkeys != Py_EMPTY_KEYS) {
-            assert(oldkeys->dk_kind != DICT_KEYS_SPLIT);
-            assert(oldkeys->dk_refcnt == 1);
 #ifdef Py_REF_DEBUG
-            _Py_RefTotal--;
+        _Py_RefTotal--;
 #endif
+        if (oldkeys == Py_EMPTY_KEYS) {
+            oldkeys->dk_refcnt--;
+            assert(oldkeys->dk_refcnt > 0);
+        }
+        else {
+            assert(oldkeys->dk_kind != DICT_KEYS_SPLIT);
+            assert(oldkeys->dk_refcnt == 1);
 #if PyDict_MAXFREELIST > 0
             struct _Py_dict_state *state = get_dict_state();
 #ifdef Py_DEBUG