pytorch

20143e5f - Revert D21245094: [resubmit] Enable global observers API

Revert D21245094: [resubmit] Enable global observers API Test Plan: revert-hammer Differential Revision: D21245094 Original commit changeset: 595e41b18206 fbshipit-source-id: 90344b361857d76ce5db75438c949dad1f5f186b