treat Parameter the same way as Tensor (#48963)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48963
This PR makes the binding code treat `Parameter` the same way as `Tensor`, unlike all other `Tensor` subclasses. This does change the semantics of `THPVariable_CheckExact`, but it isn't used much and it seemed to make sense for the half dozen or so places that it is used.
Test Plan: Existing unit tests. Benchmarks are in #48966
Reviewed By: ezyang
Differential Revision: D25590733
Pulled By: robieta
fbshipit-source-id: 060ecaded27b26e4b756898eabb9a94966fc9840
