Combine incref/steal into new stackref

Author: mpage

Python/bytecodes.c

@@ -2254,8 +2254,7 @@ dummy_func(
                 DEOPT_IF(true);
             }
             STAT_INC(LOAD_ATTR, hit);
-            Py_INCREF(attr_o);
-            attr = PyStackRef_FromPyObjectSteal(attr_o);
+            attr = PyStackRef_FromPyObjectNew(attr_o);
             UNLOCK_OBJECT(dict);
             null = PyStackRef_NULL;
             DECREF_INPUTS();