update default fusion strategy (#72038)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/72038
Test Plan: Imported from OSS
Reviewed By: navahgar
Differential Revision: D33864653
Pulled By: eellison
fbshipit-source-id: 9f0d7fa5f72a901566fae937668d3a6ede2c4b03
(cherry picked from commit aeee43e8d92255d2926a7ce0f540ffb46a681d6a)
