Remove dead named_tensors_unsupported_error definitions. (#42171)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/42171
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Test Plan: Imported from OSS
Reviewed By: pbelevich
Differential Revision: D22794980
Pulled By: ezyang
fbshipit-source-id: 250b6566270e19240361d758db55101d6fcb33e9
