Add experimental torch.export prototype (#95070)
This is WIP PR for adding torch.export API in OSS. Couple of points:
- I intentionally named it as experimental_export so that ppl don't get confused thinking this is our official API
- We don't plan to use AOTAutograd backend just yet. The reason we have it here is because the functionalization AOTAutograd uses is what we need for export (handling of param/buffer mutation etc). In the near future, I will extract the functionalization part and use it on top of make_fx. What we have right now is merely a placeholder.
- The reason we want to do it now is because we want to have some minimal tests running in OSS so that we can catch regressions earlier.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/95070
Approved by: https://github.com/gmagogsfm, https://github.com/zhxchen17
