make broadcast fastpath the default for currently rolled-out ops (#68365)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/68365
title. broadcast fastpath has been running fine for the enabled ops for a while now, so make it the default for these ops.
Test Plan: diff is a no-op, so sandcastle
Differential Revision: D32107847
fbshipit-source-id: b239b127b219985bf7df6a0eea2d879b8e9c79a4
