explicitly provide memory format when calling to clone() at TensorFactories.cpp
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/28665
Test Plan: Imported from OSS
Differential Revision: D18333361
Pulled By: ifedan
fbshipit-source-id: 88f19649e708c3e04decc1ca34c7a1faabe6c434
