Fix llama eval bug (#1549)
Summary:
Fix https://github.com/pytorch/benchmark/issues/1548 . Works for Roadmap https://github.com/pytorch/benchmark/issues/1293 for Increase benchmark coverage,
Before:
```bash
python run.py llama -d cpu
Traceback (most recent call last):
File "run.py", line 298, in <module>
m = Model(device=args.device, test=args.test, jit=(args.mode == "jit"), batch_size=args.bs, extra_args=extra_args)
File "/workspace/benchmark/torchbenchmark/util/model.py", line 20, in __call__
obj = type.__call__(cls, *args, **kwargs)
File "/workspace/benchmark/torchbenchmark/models/llama/__init__.py", line 16, in __init__
super().__init__(test=test, device=device, jit=jit, batch_size=batch_size, extra_args=extra_args)
File "/workspace/benchmark/torchbenchmark/util/model.py", line 84, in __init__
self.determine_batch_size(batch_size)
File "/workspace/benchmark/torchbenchmark/util/model.py", line 216, in determine_batch_size
raise NotImplementedError(f"Test {self.test} is not implemented.")
NotImplementedError: Test eval is not implemented.
```
After:
```bash
python run.py llama -d cpu --bs 32
Running eval method from llama on cpu in eager mode with input batch size 32.
CPU Total Wall Time: 11.997 milliseconds
CPU Peak Memory: 1.3799 GB
python run.py llama -d cpu --bs 16
Running eval method from llama on cpu in eager mode with input batch size 16.
CPU Total Wall Time: 9.870 milliseconds
CPU Peak Memory: 1.3770 GB
```
Pull Request resolved: https://github.com/pytorch/benchmark/pull/1549
Reviewed By: aaronenyeshi
Differential Revision: D45005325
Pulled By: xuzhao9
fbshipit-source-id: 265532b33f83e87fecf94eac95e29f65ad8083f4
