Introduce function-local settings for executor, expose in c++ (#74012)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/74012
This allows setting an executor on a function. The first use case is use to decompositions in C++ without additional fusion passes etc which might not work with custom tensors like batched tensors/vmap. A subsequent use case might be taking advantage of invokees of JIT execution which guard on certain properties before invocation (such as complete shapes in AOT autograd, rank in lazy tensor).
Test Plan: Imported from OSS
Reviewed By: gchanan
Differential Revision: D34938124
Pulled By: eellison
fbshipit-source-id: cf7a45416457942b872322cab47d871a8336bdb5
(cherry picked from commit 9c600eb9ad0f2173f003e511268e97584edae36d)
