Revert D25545777: [PyTorch] Use .sizes() instead of .size() in _cat_out_cpu
Test Plan: revert-hammer
Differential Revision:
D25545777 (https://github.com/pytorch/pytorch/commit/c1879b573e8cf6ff8b4c527d8dc55c04eaf61dec)
Original commit changeset: b2714fac95c8
fbshipit-source-id: f534f8fc312943f1e6ba3d4029d6cf69b006aca8
