Remove scratch buffers and redundant output from quantized lstm

* Remove scratch buffers
* Remove redundant state output
* Update tests

Test: NeuralNetworksTest_operations
Test: NeuralNetworksTest_static
Bug: 113561892
Change-Id: I93cb7567b78c10e2c2c75c1b5ada80516b427706
Merged-In: I93cb7567b78c10e2c2c75c1b5ada80516b427706
(cherry picked from commit 42fc2f949317f2941eb0c626db0fe4f5d5817b32)
10 files changed