rename macro. TORCH_LIBRARY_FRAGMENT_THIS_API_IS_FOR_PER_OP_REGISTRATION_ONLY to TORCH_LIBRARY_FRAGMENT (#47320)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/47320
Test Plan: Imported from OSS
Reviewed By: ezyang
Differential Revision: D24714806
Pulled By: bdhirsh
fbshipit-source-id: 7007c9c54b785015577ebafd8e591aa534fe0640