Clean up pytorch_android_torchvision test (#29455)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/29455
- Don't need to load native library.
- Shape is now private.
Test Plan: Ran test.
Reviewed By: IvanKobzarev
Differential Revision: D18405213
fbshipit-source-id: e1d1abcf2122332317693ce391e840904b69e135
