Op-calling API can handle state (#16177)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/16177
Change the API for calling operators so that it can store state in an OpKernel object.
This diff doesn't store the state there yet, that comes in a follow up diff.
Reviewed By: ezyang
Differential Revision: D13742889
fbshipit-source-id: 20511a9a1b9f850074e50634d4b4acf87f8c6ecd
