Specify file encoding in test_torch.py (#97628)
Attempt to fix
```
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe4 in position 5260: ordinal not in range(128)
```
in https://github.com/pytorch/pytorch/actions/runs/4522628359/jobs/7965372405
In general, it's a good practice to explicitly specify encoding, as otherwise it depends on environment variable and makes tests failures unpredicatble
Pull Request resolved: https://github.com/pytorch/pytorch/pull/97628
Approved by: https://github.com/dagitses, https://github.com/kit1980
