Moving at::Tensor into caffe2::Tensor without bumping refcount (#19388)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/19388
The old implementation forced a refcount bump when converting at::Tensor to caffe2::Tensor.
Now, it is possible to move it without a refcount bump.
Reviewed By: dzhulgakov
Differential Revision: D14986815
fbshipit-source-id: 92b4b0a6f323ed38376ffad75f960cad250ecd9b
