Revert D34818577: Remove checkout step
Revert D34818577: Remove checkout step

Differential Revision:
D34818577 (https://github.com/facebook/flipper/commit/16ab0b7148b76b11ff4bb3b4952ea98e68cc2878)

Original commit changeset: 1f34ab1d1830

Original Phabricator Diff: D34818577 (https://github.com/facebook/flipper/commit/16ab0b7148b76b11ff4bb3b4952ea98e68cc2878)

fbshipit-source-id: b21c3692e63c309b9ff4a5afcea1260b37d3ff31

facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper