Create byte-aware word lstm benchmark (#31260)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/31260
1. Update the LiteLM dataset conversion script (fbcode/pytext/fb/tools/lite_lm_dataset_to_tensorproto.py)
2. Created a benchmark json file for byte-aware lstm word model (xplat/aibench/specifications/models/caffe2/assistant/lite_lm_len5.json)
3. In order to run the model -- created an int64 Tensor for the model, added batch gather ops to the BUCK file
Test Plan:
```
1. Create tensorproto of the model input
buck run mode/opt //pytext/fb/tools:byte_lm_dataset_to_tensorproto -- --in-path /mnt/vol/pytext/smart_keyboard/aibench/test_5.txt --out-path /mnt/vol/pytext/smart_keyboard/aibench/byteAwareWordLM/ --hidden_dim 203 --layers_num 2 --max_seq_len 64 --max_byte_len 15
2. Run the aibench command
buck run fbsource//xplat/aibench:run_bench -- -b aibench/specifications/models/caffe2/assistant/lm_byte_lstm_len5.json --remote --devices SM-G960U-8.0.0-26
```
Reviewed By: gardenia22
Differential Revision: D17785682
fbshipit-source-id: 351c3c8bae16449e72ac641522803b23a83349be
