Port `argmin` kernel to structured kernels. (#59938)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/59938
Tracking issue: #55070
Test Plan: Imported from OSS
Reviewed By: soulitzer
Differential Revision: D29104396
Pulled By: ezyang
fbshipit-source-id: 39c59bcc044649c1ec9c9685366c4dda87f76aa7
