[inductor] Implement bucketize() for dependencies.py (#105102)
dependencies.py is used for tracking reads and writes, which is used for identifying dependencies between buffers: i.e. if buffer X reads buffer Y, then X depends on Y. ops.bucketize() reads from an offsets tensor, so we should track it in dependencies.py to correctly track dependencies. Since bucketize performs a binary search over the offsets tensor, the dependency is marked as a StarDep to indicate that the entire tensor is needed.
Use case: we find that jagged tensor dense_to_jagged ops - which use bucketize() to map jagged indices to dense indices - perform better if the bucketize() kernel is separated from the gather kernel. Previously, because bucketize() wasn't marked as reading anything, it would just get inlined.
Differential Revision: [D47422704](https://our.internmc.facebook.com/intern/diff/D47422704)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/105102
Approved by: https://github.com/eellison
