Revert D29801875: .github: Clone pytorch to separate directory
Test Plan: revert-hammer
Differential Revision:
D29801875 (https://github.com/pytorch/pytorch/commit/a152c12d7bc29929660edbc7db272afc5179f78e)
Original commit changeset: 71a3c7c949e5
fbshipit-source-id: 85175a9933d1e33117b1461d5a760e1a79f60047
