Pass Tensor instead of Tensor& to torch::nn functionals that can change input in place (#30112)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/30112
Currently, we have torch::nn functionals that takes `input` as `Tensor&` in order to be able to in-place change `input`'s value. We likely shouldn't do this because it will prevent the following use case:
```cpp
F::elu(torch::tensor(1), F::ELUFuncOptions().inplace(true))
```
The solution is to change the type of `input` to `Tensor`, so that we can pass an rvalue into the functional.
Test Plan: Imported from OSS
Differential Revision: D18601580
Pulled By: yf225
fbshipit-source-id: 639a86eb62f6c986b0f20bf7e201983e83126e73
