[Checkpoint][2D][5/N] Add checkpoint_utils for distributed checkpoint to testing/_internal/distributed/ (#89873)
Moving checkpoint_utils from Tau: https://github.com/wz337/PiPPy/blob/6acf4054cfd10c8377d65fa1e4f18230d6711edd/spmd/testing/checkpoint_utils.py
Checkpoint_utils: add a wrapper to initialize a temp directory for checkpoint testing.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/89873
Approved by: https://github.com/XilunWu, https://github.com/awgu, https://github.com/fduwjj
