Model support for `llama_v2_7b_16h` with Torch_XLA2

[ManfeiBai]

Fix the model test for llama_v2_7b_16h.py

1. setup env according to Run a model under torch_xla2
2. Run model test under run_torchbench/ with python models/your_target_model_name.py
3. Fix the failure.

Please refer to
this guide as guide to fix:

Also refer to these PRs:

• Add documentation on fixing a torchbench model on torchxla2 #7583

[barney-s]

 % JAX_PLATFORMS=cpu python models/llama_v2_7b_16h.py                                                                                                                                                                                                                                  

/usr/local/google/home/barni/miniconda3/envs/diffusion-models-2/lib/python3.10/site-packages/torch/distributed/distributed_c10d.py:337: UserWarning: Device capability of jax unspecified, assuming `cpu` and `cuda`. Please specify it via the `devices` argument of `register_backend`.
  warnings.warn(
We detected that you are passing `past_key_values` as a tuple and this is deprecated and will be removed in v4.43. Please use an appropriate `Cache` class (https://huggingface.co/docs/transformers/v4.41.3/en/internal/generation_utils#transformers.Cache)
WARNING:root:Duplicate op registration for aten.trunc
Traceback (most recent call last):
  File "/usr/local/google/home/barni/workspace/pytorch-tpu/run_torchbench/models/llama_v2_7b_16h.py", line 60, in <module>
    sys.exit(main())
  File "/usr/local/google/home/barni/workspace/pytorch-tpu/run_torchbench/models/llama_v2_7b_16h.py", line 39, in main
    xla2_ans = model(**example)
  File "/usr/local/google/home/barni/miniconda3/envs/diffusion-models-2/lib/python3.10/site-packages/torch/nn/modules/module.py", line 1736, in _wrapped_call_impl
    return self._call_impl(*args, **kwargs)
  File "/usr/local/google/home/barni/miniconda3/envs/diffusion-models-2/lib/python3.10/site-packages/torch/nn/modules/module.py", line 1747, in _call_impl
    return forward_call(*args, **kwargs)
  File "/usr/local/google/home/barni/miniconda3/envs/diffusion-models-2/lib/python3.10/site-packages/transformers/models/llama/modeling_llama.py", line 1189, in forward
    outputs = self.model(
  File "/usr/local/google/home/barni/miniconda3/envs/diffusion-models-2/lib/python3.10/site-packages/torch/nn/modules/module.py", line 1736, in _wrapped_call_impl
    return self._call_impl(*args, **kwargs)
  File "/usr/local/google/home/barni/miniconda3/envs/diffusion-models-2/lib/python3.10/site-packages/torch/nn/modules/module.py", line 1747, in _call_impl
    return forward_call(*args, **kwargs)
  File "/usr/local/google/home/barni/miniconda3/envs/diffusion-models-2/lib/python3.10/site-packages/transformers/models/llama/modeling_llama.py", line 977, in forward
    position_embeddings = self.rotary_emb(hidden_states, position_ids)
  File "/usr/local/google/home/barni/miniconda3/envs/diffusion-models-2/lib/python3.10/site-packages/torch/nn/modules/module.py", line 1736, in _wrapped_call_impl
    return self._call_impl(*args, **kwargs)
  File "/usr/local/google/home/barni/miniconda3/envs/diffusion-models-2/lib/python3.10/site-packages/torch/nn/modules/module.py", line 1747, in _call_impl
    return forward_call(*args, **kwargs)
  File "/usr/local/google/home/barni/miniconda3/envs/diffusion-models-2/lib/python3.10/site-packages/torch/utils/_contextlib.py", line 116, in decorate_context
    return func(*args, **kwargs)
  File "/usr/local/google/home/barni/miniconda3/envs/diffusion-models-2/lib/python3.10/site-packages/transformers/models/llama/modeling_llama.py", line 208, in forward
    with torch.autocast(device_type=device_type, enabled=False):
  File "/usr/local/google/home/barni/miniconda3/envs/diffusion-models-2/lib/python3.10/site-packages/torch/amp/autocast_mode.py", line 256, in __init__
    assert hasattr(self.custom_device_mod, func), (
AssertionError: Tried to use AMP with the `jax` backend, but the backend has not registered a module or  the module miss some necessary funcs. The backend should register a module by `torch._register_device_module`, and the module must have these funcs: 
`get_amp_supported_dtype() -> List[torch.dtype]`. 
But the func `get_amp_supported_dtype` is missing. 

[barney-s]

pytorch-tpu/run_torchbench#7