explicitly provide memory format when calling to clone() at SparseTensorMath.cpp
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/28700
Test Plan: Imported from OSS
Differential Revision: D18333349
Pulled By: ifedan
fbshipit-source-id: 23780c6a60f366de2b8f563b477df35cf52f88b4
