fix runtime crash when rnn model inference, test=develop (#31833)#31846

Merged

Superjomn merged 1 commit intoPaddlePaddle:release/2.0from winter-wang:fix_rnn_bug

Mar 25, 2021

+18-17

Commits on Mar 24, 2021

fix runtime crash when rnn model inference, test=develop (PaddlePaddle#31833 )
winter-wang
committed