Created by: songyouwei

It is required that the LoDTensor in sequence related OP unittests must be obtained by self.get_sequence_batch_size_1_input() function to cover the case of batch size = 1.

wiki: https://github.com/PaddlePaddle/Paddle/wiki/It-is-required-to-include-LoDTensor-input-with-batch_size=1-in-sequence-OP-test

test case1: white list does not have sequence_concat op, and its unittest does not have required function call. test result1:

test case2: white list updated. test result2: http://ci.paddlepaddle.org/viewLog.html?buildId=269728&buildTypeId=YYTest_PrCiCpuPy2&tab=buildLog&branch_YYTest=pull%2F21615