Add generate-wrapper.py with its generated wrapper files. (#28285)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/28285
1. Add generate-wrapper.py to route different code path base on different platform.
2. Append all the generated wrapper files by running generate-wrapper.py, and they will be used in the next diff for buck build targets.
ghstack-source-id: 92071247
Test Plan: Will be tested in the next diff when these files are linked.
Reviewed By: dreiss
Differential Revision: D17967339
fbshipit-source-id: 8af88af9e8d2e4640bcf9d29c4daf10666aa88dc
