Implement name inference rule for empty_like, clone (#23746)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/23746
`torch.empty_like(tensor)` and `tensor.clone()` both propagate names to
the output tensor.
As a part of this change, I fixed the empty(..., names=) overload to
include the `memory_format` argument in the normal `empty` declaration
in native_functions.yaml.
Test Plan: - [namedtensor ci]
Differential Revision: D16647821
Pulled By: zou3519
fbshipit-source-id: 43b261f3456b6bf5fca7b6313e659b259a2ba66d
