Revert D23242101: [pytorch][PR] Implement first draft of autograd benchmark.
Test Plan: revert-hammer
Differential Revision:
D23242101 (https://github.com/pytorch/pytorch/commit/c2511bdfa4bef89e6c328a161d3a4d3466261ff7)
Original commit changeset: a2b92d5a4341
fbshipit-source-id: bda562d15565f074b448022d180ec8f959c6ecc9
