Remove unused methods about Node::class_id_

src/global-handles.h

Index: src/global-handles.h
diff --git a/src/global-handles.h b/src/global-handles.h
index 7808d16a03f6e930829671550c5a7bd56b2c7518..a28a96f367c0576a0426a3ef8da7a8eb1f4d72a6 100644
--- a/src/global-handles.h
+++ b/src/global-handles.h
@@ -130,9 +130,6 @@ class GlobalHandles {
                 void* parameter,
                 WeakReferenceCallback callback);
 
-  static void SetWrapperClassId(Object** location, uint16_t class_id);
-  static uint16_t GetWrapperClassId(Object** location);
-
   // Returns the current number of weak handles.
   int NumberOfWeakHandles() { return number_of_weak_handles_; }