Optim foreach cleanup for Rprop (#70483)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/70483
Test Plan: Imported from OSS
Reviewed By: anjali411
Differential Revision: D33767866
Pulled By: mikaylagawarecki
fbshipit-source-id: ffc5ae68eeea8fa09385862b853b731554b77bcb
(cherry picked from commit 3a0fe295807bb4519884a1838edeea1a9d222e41)
