[inductor] Add lowering for aten.unfold (#105165)
The decomposition for unfold uses `as_strided` which forces the input to be
realized. Instead, this implements it as a `GenericView` with reindexing
which removes the need to realize, though it does call `mark_reuse` incase
the input computation is expensive and the windows overlap.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/105165
Approved by: https://github.com/lezcano, https://github.com/jansel
