Implement a constructor for nested_tensor that is similar to torch.tensor() (#88213)
Summary: This diff merges both previous implementations of constructors for nested tensors, the one from lists of tensors and the one with arbitrary python lists, adn implements it in pytorch core so no extensions are needed to construct NT.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/88213
Approved by: https://github.com/cpuhrsch
Author
Antoni Viros i Martin
