pytorch

baa227b4 - Revert D17579439: Add std::variant backport as torch::variant

Revert D17579439: Add std::variant backport as torch::variant Test Plan: revert-hammer Differential Revision: D17579439 Original commit changeset: 6416521047f5 fbshipit-source-id: 0a57bef5d1d2d5366f84fcfa52b3968e01802164