Reference implementations for softmax, log_softmax, logsumexp (#79423)
This PR adds references for:
- `torch.softmax`
- `torch.log_softmax`
- `torch.logsumexp`
Unfortunately, none of them currently pass `test_python_ref_executor` even with `"aten"` executor.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/79423
Approved by: https://github.com/mruberry
