Revert D31238123: [pytorch][PR] Avoid saving self for`softmax` and `log_softmax`
Test Plan: revert-hammer
Differential Revision:
D31238123 (https://github.com/pytorch/pytorch/commit/fb412bdd80a04e648492dd26c3400a87e8490198)
Original commit changeset: afd319d3676d
fbshipit-source-id: b7980d653a4b8322a225f1dd08c2857ecbe5bc94
