Implement name inference for expand (#24469)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/24469
tensor.expand(*sizes) returns a tensor with names equal to tensor.names
plus unnamed padding in the beginning dimensions.
For example, Tensor[H, W].expand(10, 2, 128, 128) -> Tensor[None, None,
H, W].
Test Plan: - new tests [namedtensor ci]
Differential Revision: D16915804
Pulled By: zou3519
fbshipit-source-id: 77ac97f42e9959d7f6d358c5286e3dc27488e33d
