Delete dead TensorOptions::key_set (#54004)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/54004
According to
`glean-search find-decls --refs 'c10::TensorOptions::key_set'`
there are no uses of this function
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Test Plan: Imported from OSS
Reviewed By: bdhirsh
Differential Revision: D27047971
Pulled By: ezyang
fbshipit-source-id: 63662dd7ab27753ecb79c45c152c2cad1160dab2
