Fix deprecated python "add" calls (#33428)
Summary:
This PR fixed those python "add" calls using deprecated signature `add(Scalar, Tensor)`. The alternative signature `add(Tensor, alpha = Scalar)` is used.
cc csarofeen zasdfgbnm ptrblck ngimel
Pull Request resolved: https://github.com/pytorch/pytorch/pull/33428
Differential Revision: D20002534
Pulled By: vincentqb
fbshipit-source-id: 81f2dd6170a47a9b53a17e5817c26e70d8afa130
