add torch.tensor requires grad (#19445)
Summary:
Add setting requires_grad = True within torchscript to torch.Tensor
Within constant propagation, we can't insert any constants that require grad.
Also added shape analysis and requires grad analysis to torch.tensor
Pull Request resolved: https://github.com/pytorch/pytorch/pull/19445
Differential Revision: D15046211
Pulled By: eellison
fbshipit-source-id: b4ef7a6b4b6b8dc03e1fa49f87dc415874cd1998
