Created by: 1024er

cherry pick error infor PRs to release/1.8

修改报错信息 paddle.fluid.layers.gather_tree paddle.fluid.layers.GRUCell paddle.fluid.layers.gru_unit paddle.fluid.layers.lstm paddle.fluid.layers.LSTMCell paddle.fluid.layers.lstm_unit paddle.fluid.layers.rnn paddle.fluid.layers.RNNCell