export tools/autograd to torchgen package (#106663)
Fixes #ISSUE_NUMBER
as discussed here https://github.com/pytorch/pytorch/pull/105003, I have exported tools/autograd to torchgen package, and could you have a look? @zou3519
Pull Request resolved: https://github.com/pytorch/pytorch/pull/106663
Approved by: https://github.com/zou3519
