[fix] torch.cat: Don't resize out if it is already of the correct size. (#49937)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/49878
Pull Request resolved: https://github.com/pytorch/pytorch/pull/49937
Reviewed By: mruberry
Differential Revision: D25851564
Pulled By: ngimel
fbshipit-source-id: 9a78922642d5bace70d887a88fa9e92d88038120
