Revert D26723384: [pytorch][PR] Implements `torch.linalg.lstsq`
Test Plan: revert-hammer
Differential Revision:
D26723384 (https://github.com/pytorch/pytorch/commit/3ac90132351b3dab51d6ecede52db62e101257e1)
Original commit changeset: c9866a95f140
fbshipit-source-id: 3e5263d71facdc91ca09d7dcbbbe3ba818ee2821
