Add quantized LSTM op.

Bug: 144841609

Test: NeuralNetworksTest_static

Change-Id: I8aab51695382211e003d8fc442d33bae3006dc13
Merged-In: I8aab51695382211e003d8fc442d33bae3006dc13
(cherry picked from commit c8b0cd33b92db195e125171d7a1360af59a3ab8c)
3 files changed