[iOS GPU] Remove unnecessary texture size changing (#54108)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/54108
Clean up the hardcode for 2d tensors.
ghstack-source-id: 124113406
Test Plan:
```
2021-03-16 00:27:31.280761-0700 PyTorchPlayground[16024:6249832] [bool test_view()],[1 10 2 2 ],[SUCCEED]
2021-03-16 00:27:31.282833-0700 PyTorchPlayground[16024:6249832] [bool test_view2()],[1 10 2 2 ],[SUCCEED]
2021-03-16 00:27:31.285320-0700 PyTorchPlayground[16024:6249832] [bool test_view3()],[5 8 ],[SUCCEED]
2021-03-16 00:27:31.286929-0700 PyTorchPlayground[16024:6249832] [bool test_view4()],[5 8
```
- Sandcastle CI
- CircleCI
Reviewed By: SS-JIA
Differential Revision: D27075236
fbshipit-source-id: 1005fd82f4a75603697579a191d3acc6fc1bd690
