cudnnRNNForwardInferenceEx doesn't support 0 sequence in the bathes
Fix issue that cudnnRNNForwardInferenceEx doesn't support 0 sequence in the bathes
Solution:
Reset the 0 sequence to 1 for the bathes before call the cudnnRNNForwardInferenceEx, has a array to track the batch id which has 0 sequence. Once get the result, call a CUDA kernel to mask on the output using the batch id tracked in the array.