Add some shape decomps (t, transpose, rot90, stack)
Also fixes xlogy (turns out the only thing it was missing was a type cast annotation! nice!)
I also renamed `canonicalize_idx` => `canonicalize_dim` (to align with `canonicalize_dims`) and fixed a bug in it (cc: @mruberry)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/76873
Approved by: https://github.com/mruberry
