Revert D26113953: [pytorch][PR] [ZeroRedundancyOptimizer] Elastic and pytorch compatible checkpoints
Test Plan: revert-hammer
Differential Revision:
D26113953 (https://github.com/pytorch/pytorch/commit/bbe18e35275c9c6116ebc27be40e8c6220b98a9a)
Original commit changeset: 030bfeee2c34
fbshipit-source-id: 6c1494ad01c2f96a15601329b4fce3fef4b38a01
