Don't register a fallback for private use to let extensions do it themselves (#44149)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/44149
Thanks Christian Puhrsch for reporting.
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Test Plan: Imported from OSS
Reviewed By: izdeby
Differential Revision: D23574739
Pulled By: ezyang
fbshipit-source-id: 8c9d0d78e6970139e0103cd1e0004b743e3c7f9e
