Use variable_data() in tensor_to_numpy (#22214)
Summary:
As part of the Variable/Tensor merge, we want to gradually remove call sites of `tensor_data()` and the API itself, and instead uses `variable_data()`. This PR removes the `tensor_data()` call in the tensor_to_numpy conversion path.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/22214
Differential Revision: D15997397
Pulled By: yf225
fbshipit-source-id: 6fcab7b14e138824fc2adb5434512bcf868ca375
