Implemented Martin's suggestion to clear the free lists during the garbage collection of the highest generation.
diff --git a/Include/classobject.h b/Include/classobject.h
index 8f8db7d..118dd09 100644
--- a/Include/classobject.h
+++ b/Include/classobject.h
@@ -74,6 +74,7 @@
 
 PyAPI_FUNC(int) PyClass_IsSubclass(PyObject *, PyObject *);
 
+PyAPI_FUNC(int) PyMethod_ClearFreeList(void);
 
 #ifdef __cplusplus
 }