Seed `Shuffler` for MP DataLoader without explicit `manual_seed`. (#77855)
Follow up on https://github.com/pytorch/pytorch/pull/77741
This PR guarantees the `Shuffler` in first iteration with MP DataLoader has the same seed across worker processes when users don't specify the seed.
Check newly added tests
Pull Request resolved: https://github.com/pytorch/pytorch/pull/77855
Approved by: https://github.com/NivekT
