Remove export PYTHONPATH hacks (#61487)
Summary:
Remove `export PYTHONPATH=$PWD` in favor of `-m`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/61487
Test Plan: Let's see if CI passes
Reviewed By: 1ntEgr8
Differential Revision: D29645544
Pulled By: janeyx99
fbshipit-source-id: 841aea8ebed2cb1c7dbc68754b5fbdee932559c2
