remove dead torch_pb.h library (#97599)
This is only used in one place, ensure it still builds.
Differential Revision: [D44395699](https://our.internmc.facebook.com/intern/diff/D44395699/)
**NOTE FOR REVIEWERS**: This PR has internal Meta-specific changes or comments, please review them on [Phabricator](https://our.internmc.facebook.com/intern/diff/D44395699/)!
Pull Request resolved: https://github.com/pytorch/pytorch/pull/97599
Approved by: https://github.com/PaliC
