Make lazy codegen honor per-operator-headers flag (#74450)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/74450
- per-operator-headers is a strict build mode where compulation units aren't allowed
to depend on bulk headers like ATen/Functions.h, but must instead depend only on the
specific operator headers used. (In other configurations, the reverse is required).
Test Plan: CI to make sure nothing breaks for existing backends, and rebased next diff manual test to make sure it actually helps
Reviewed By: ezyang, bdhirsh
Differential Revision: D35002666
fbshipit-source-id: 712445f8d146cf026759444fbd42a20705be9bef
(cherry picked from commit f13e5522d49a6edcb6aed4431b1ec8e2b50a98fc)
