[PrimTorch] Add reference for torch.norm (#81765)
This ref does more things than `torch.norm`, and it fixes a few bugs
that `torch.norm` has. This implementation and the `torch.norm`
implementation come to terms in the next PR of this stack
We put this PR before, as otherwise `test_decomp.py` was failing.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/81765
Approved by: https://github.com/ngimel
