pytorch

257b6149 - Revert D17610292: [pytorch][PR] Choose num_threads in parallel_for based on GRAIN_SIZE

Revert D17610292: [pytorch][PR] Choose num_threads in parallel_for based on GRAIN_SIZE Test Plan: revert-hammer Differential Revision: D17610292 Original commit changeset: 60b9fe4b0eec fbshipit-source-id: cfa0be39eef5bf306ef128c134f86a135bb3d5c9