Use plain power operator in Adam/Adamw when capturing (#104254)
The goal is to fix the problem from https://github.com/pytorch/pytorch/pull/102858
The full error this used to raise was :
```
2023-06-27T15:12:15.0663239Z File "/opt/conda/envs/py_3.10/lib/python3.10/site-packages/torch/optim/adamw.py", line 409, in _single_tensor_adamw
2023-06-27T15:12:15.0663699Z bias_correction1 = 1 - beta1 ** step
2023-06-27T15:12:15.0664200Z File "/opt/conda/envs/py_3.10/lib/python3.10/site-packages/torch/_tensor.py", line 40, in wrapped
2023-06-27T15:12:15.0664547Z return f(*args, **kwargs)
2023-06-27T15:12:15.0665031Z File "/opt/conda/envs/py_3.10/lib/python3.10/site-packages/torch/_tensor.py", line 882, in __rpow__
2023-06-27T15:12:15.0665483Z return torch.tensor(other, dtype=dtype, device=self.device) ** self
2023-06-27T15:12:15.0665899Z RuntimeError: CUDA error: operation not permitted when stream is capturing
2023-06-27T15:12:15.0666401Z CUDA kernel errors might be asynchronously reported at some other API call, so the stacktrace below might be incorrect.
```
This pow issue was fixed in https://github.com/pytorch/pytorch/pull/104264 and so this problem should be solvable now.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/104254
Approved by: https://github.com/janeyx99, https://github.com/aws-murandoo
