Jit save/load meta tensors (#73435)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/73435
Add support for torch.jit.save and load for meta tensors to use in meta tensor based xl weights.
Test Plan:
```
buck test //caffe2/test:jit && -- -r .*save_load_meta_tensors.*
```
Reviewed By: houseroad
Differential Revision: D34479511
fbshipit-source-id: 117ccb12e9e427290a17297204508ec85495e3be
(cherry picked from commit ee9aaaf8208d6c9530c828a4b9f28cf2cca05630)
