Revert D25719980: [pytorch][PR] Accept input tensor with 0-dim batch size for MultiLabelMarginLoss
Test Plan: revert-hammer
Differential Revision:
D25719980 (https://github.com/pytorch/pytorch/commit/6b56b71e61e14bf4de5b371f0d8f2f2029065b31)
Original commit changeset: 83414bad37c0
fbshipit-source-id: 27eddd711a2b9e0adbc08bfab12100562e63ac21
