Created by: chenwhql

Add input->lod().empty() check in the following 14 ops' Compute function, make the input type error hints are more user friendly.

sequence_concat_op.h
sequence_conv_op.h
sequence_enumerate_op.h
sequence_erase_op.h
sequence_expand_as_op.h
sequence_expand_op.h
sequence_pad_op.h
sequence_pool_op.h
sequence_reshape_op.h
sequence_reverse_op.h
sequence_scatter_op.h
sequence_slice_op.h
sequence_softmax_op.h
sequence_topk_avg_pooling_op.h

The result is like

These two ops doesn't use the LoD info of Input, so no check added.

sequence_mask_op.h
sequence_unpad_op.h

Test case

import numpy
import paddle.fluid as fluid

x = fluid.layers.data(name='x', shape=[10,10], append_batch_size=False, dtype='float32')
x_conved = fluid.layers.sequence_last_step(input=x)

place = fluid.CPUPlace()
exe = fluid.Executor(place)

input = numpy.random.random([10,10]).astype('float32')
exe.run(fluid.default_main_program(), feed={'x': input})