Port empty_strided to ATen. (#15948)
Summary:
Turns out this has basically been implemented already in Resize.h / Resize.cuh.
Also added some testing, basically just to check that empty_strided behaves equivalently to as_strided.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/15948
Differential Revision: D13631098
Pulled By: gchanan
fbshipit-source-id: eb0e04eead45e4cff393ebde340f9d265779e185
