generate xla codegen in-tree (#55050)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/55050
not ready for review yet
Test Plan: Imported from OSS
Reviewed By: ezyang
Differential Revision: D27708346
Pulled By: bdhirsh
fbshipit-source-id: 2289edd641f30277d7561cf2d48ec69c6a2137a9
