Make empty_cpu sanity test CPU only in DEBUG mode (#51358)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51358
BackendSelect is expected to enforce this invariant.
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Test Plan: Imported from OSS
Reviewed By: swolchok
Differential Revision: D26149502
Pulled By: ezyang
fbshipit-source-id: f53ab66e8324b729a4057b376fe3d60b14daf2fb
