[Doc] `make_tensor` to `torch.testing` module (#63925)
Summary:
This PR aims to add `make_tensor` to the `torch.testing` module in PyTorch docs.
TODOs:
* [x] Add examples
cc: pmeier mruberry brianjo
Pull Request resolved: https://github.com/pytorch/pytorch/pull/63925
Reviewed By: ngimel
Differential Revision: D30633487
Pulled By: mruberry
fbshipit-source-id: 8e5a1f880c6ece5925b4039fee8122bd739538af
