Remove lowered execution (#21674)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21674
ghimport-source-id: b8e27f0ce9b8b362daf73556ee67457fb5355062
Reviewed By: eellison
Differential Revision: D15777726
Pulled By: zdevito
fbshipit-source-id: 718ac676c9a1bcf99b856862fd29631d825645da
