fmod: Port to structured (#60809)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/60809
Test Plan: Imported from OSS
Reviewed By: mruberry
Differential Revision: D29449378
Pulled By: ezyang
fbshipit-source-id: 70f6fa95988f753eec4aefa60a60dddb7f3d744e
