[Operator Versioning] Split the upgrader test to a separate file and cover mobile part (#70090)
Summary:
1. Split the test `test_save_load.py` to two files. Basically move the operator versioning related changes to `test_save_load_for_op_versions.py`.
2. Add mobile module related test to `test_save_load_for_op_versions.py`
How to run:
```
buck test mode/opt //caffe2/test:jit
or
python test/test_jit.py TestSaveLoadForOpVersion
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/70090
ghstack-source-id: 146103547
Test Plan:
```
buck test mode/opt //caffe2/test:jit
python test/test_jit.py TestSaveLoadForOpVersion
```
Reviewed By: tugsbayasgalan
Differential Revision: D33180767
fbshipit-source-id: dd31e313c81e90b598ea9dd5ad04a853c017f994
