Change some comments related to moving copy_ to native (#19618)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/19618
ghimport-source-id: 6bb9965f2f7b72f602f03e27b664d7d7696edd00
Differential Revision: D15048632
Pulled By: li-roy
fbshipit-source-id: a2707e3086f3a9993780a7f76104c5f00f2a9618
