[Inductor] [FX passes] Group linear fusion (#105116)
Summary:
The draft version of a group + batch fusion framework, and the group linear fusion implementation.
In the future, it's pretty straightforward to add a new group/batch fusion policy by defining a class with match + fuse functions.
Test Plan: buck2 test 'fbcode//mode/dev-nosan' fbcode//caffe2/test/inductor:group_batch_fusion
Differential Revision: D46956695
Pull Request resolved: https://github.com/pytorch/pytorch/pull/105116
Approved by: https://github.com/jansel
