core/vm: don't call SetCode after contract creation if initcode didn't return anything (ethereum#32916)

The code change is a noop here, and the tracing hook shouldn't be
invoked if the account code doesn't actually change.

Author: jwasinger

core/vm/evm.go

@@ -601,7 +601,9 @@ func (evm *EVM) initNewContract(contract *Contract, address common.Address) ([]b
 		}
 	}
 
-	evm.StateDB.SetCode(address, ret, tracing.CodeChangeContractCreation)
+	if len(ret) > 0 {
+		evm.StateDB.SetCode(address, ret, tracing.CodeChangeContractCreation)
+	}
 	return ret, nil
 }