Add USE_NAMEDTENSOR compilation flag. (#20162)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20162
ghimport-source-id: 0efcd67f04aa087e1dd5faeee550daa2f13ef1a5
Reviewed By: gchanan
Differential Revision: D15278211
Pulled By: zou3519
fbshipit-source-id: 6fee981915d83e820fe8b50a8f59da22a428a9bf