Revert D31317680: [pytorch][PR] Avoid saving self for`softmax` and `log_softmax`
Test Plan: revert-hammer
Differential Revision:
D31317680 (https://github.com/pytorch/pytorch/commit/5f7cadc7aa4b2bad29560eca081001d162f6b171)
Original commit changeset: b3b921e06775
fbshipit-source-id: 1bca0672383536a2c21243ceb52349c766a94344
