Remove _save_data() and _load_data() from mobile (#57879)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/57879
_save_data() and _load_data() were designed as a protocol of data serialization of trainer client. As confirmed with kwanmacher and dreiss , they are not used. In addition, there's no plan to use them in Federated Learning flow. Remove them for now.
Test Plan: Imported from OSS
Reviewed By: kwanmacher
Differential Revision: D28306682
Pulled By: iseeyuan
fbshipit-source-id: 1b993ce4d78e372ae9b83bcbe496a196f9269d47
