use reshape when possible in broadcasting (#53326)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/53326
Test Plan: Imported from OSS
Reviewed By: Krovatkin
Differential Revision: D26897275
Pulled By: eellison
fbshipit-source-id: 44278633a1e6429db43443ca689b97d5a077a15c
