[FSDP][state_dict][optim_state_dict] Log slow optim and model state_dict paths (#108290)
This PR adds SimpleProfiler for FSDP state_dict/load_state_dict logging purpose. SimpleProfiler use class variables to record profiling results and it does everything in the Python which can be slow. So it is only suitable for logging slow actions such as initialization and state_dict/load_state_dict.
This PR uses SimpleProfiler to log some critical/slow paths of the model and optimizer state_dict/load_state_dict.
Differential Revision: [D48774406](https://our.internmc.facebook.com/intern/diff/D48774406/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/108290
Approved by: https://github.com/wz337
