Revert D20496044: [pytorch][PR] Change AccumulateGrad to yield `.grad`s that match weights' memory layout
Test Plan: revert-hammer
Differential Revision:
D20496044
Original commit changeset: 248d680f4b1b
fbshipit-source-id: 6462b25e3fb9c8596c1da443389089f09c32df4d
