[Reland] Update native_functions.yaml to add DefaultBackend. (#46236)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/46236
Test Plan: Imported from OSS
Reviewed By: Krovatkin
Differential Revision: D24273378
Pulled By: ailzhang
fbshipit-source-id: bed1d4c84c0bba88a7da4d9bd2ccaa58253cf91e
