Make tensordot resize output tensor's size if out= argument is specified & make it safely cast & copy output (#56286)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/56022.
Fixes https://github.com/pytorch/pytorch/issues/56316
For `torch.tensordot`,
1. `tensordot`'s out variant now resizes the output tensor provided as the `out` argument if necessary.
2. Added a check to verify if the output tensor provided as the argument for `out` is on the same device as the input tensors.
3. Added a check to verify if the dtype of the result is castable to the dtype of the output tensor provided as an argument for `out`.
4. Because of (2) & (3), `tensordot`'s out variant now [safely casts & copies output](https://github.com/pytorch/pytorch/wiki/Developer-FAQ#how-does-out-work-in-pytorch).
5. `test_tensordot` in `test_linalg.py` had a bug - the output tensor wasn't being defined to be on the same device as the input tensors. It was fixed by simply using a `device` argument in its definition.
6. Added an `OpInfo` for `tensordot` and modified the `OpInfo` for `inner`.
cc heitorschueroff mruberry
Pull Request resolved: https://github.com/pytorch/pytorch/pull/56286
Reviewed By: ngimel
Differential Revision: D27845980
Pulled By: mruberry
fbshipit-source-id: 134ab163f05c31a6900dd65aefc745803019e037
