fixed two mutex usage bugs (#9004)

op-chain-ops/state/memory_db.go

@@ -179,8 +179,8 @@ func (db *MemoryStateDB) SetCode(addr common.Address, code []byte) {
 }
 
 func (db *MemoryStateDB) GetCodeSize(addr common.Address) int {
-	db.rw.Lock()
-	defer db.rw.Unlock()
+	db.rw.RLock()
+	defer db.rw.RUnlock()
 
 	account, ok := db.genesis.Alloc[addr]
 	if !ok {
@@ -232,6 +232,9 @@ func (db *MemoryStateDB) SetState(addr common.Address, key, value common.Hash) {
 }
 
 func (db *MemoryStateDB) DeleteState(addr common.Address, key common.Hash) {
+	db.rw.Lock()
+	defer db.rw.Unlock()
+
 	account, ok := db.genesis.Alloc[addr]
 	if !ok {
 		panic(fmt.Sprintf("%s not in state", addr))