Fix `CosineAnnealingLR` on restart
Fixes #60265
The initial LR for this scheduler is not consistent when a new instance is created with `last_epoch != -1`
Maybe we can refactor the testing code to test `last_epoch != -1` in schedulers that can recreate their state from the current epoch?
Pull Request resolved: https://github.com/pytorch/pytorch/pull/60339
Approved by: https://github.com/albanD
