Switch Shuffler to use iter-local buffer (#64195)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/64195
Test Plan: Imported from OSS
Reviewed By: H-Huang
Differential Revision: D30642947
Pulled By: ejguan
fbshipit-source-id: d4b52479b4ae37ad693388b9cdb8eed83a136474
