8302670: use-after-free related to PhaseIterGVN interaction with Unique_Node_List and Node_Stack

src/hotspot/share/opto/phaseX.hpp

@@ -64,7 +64,7 @@ class NodeHash : public AnyObj {
 public:
   NodeHash(Arena *arena, uint est_max_size);
 #ifdef ASSERT
-  ~NodeHash();
+  ~NodeHash();                  // Unlock all nodes upon destruction of table.
 #endif
   Node  *hash_find(const Node*);// Find an equivalent version in hash table
   Node  *hash_find_insert(Node*);// If not in table insert else return found node