Port nextafter to structured (#57625)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/57625
Test Plan: Imported from OSS
Reviewed By: VitalyFedyunin
Differential Revision: D28224828
Pulled By: ezyang
fbshipit-source-id: 560f1bf942ea14ea6d8b915753aec83d1168005e
