pytorch

28392502 - refactor fx2trt example script so it can be imported as a library (#63262)

refactor fx2trt example script so it can be imported as a library (#63262) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/63262 Just create a `__main__` guard. Test Plan: run linter, sandcastle tests Reviewed By: 842974287 Differential Revision: D30263617 fbshipit-source-id: 8044ce5d815b043c3778591384cb13d9a89d0048