[iOS GPU][BE][3/n] Give MPSImage objects a label for better debugging experience (#60282)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/60282
1. Adds a label to the MPSImage objects. The label describes the size of the image.
2. Remove `[image markRead]`.
3. Rename two APIs for better naming convention.
ghstack-source-id: 131839557
Test Plan:
1. CircleCI
2. buck test pp-mac
Reviewed By: SS-JIA
Differential Revision: D29232975
fbshipit-source-id: 075175c4b5a1c5b79e795f4860e1694d7c06d4f2
