[spmd] Add list handling to data parallel and add foreach tests (#99373)
This PR adds list handling logic to the new DataParallel expansion and
add foreach optimizer tests, currently current testing sgd optimizers
in foreach mode, for both replicate and fully shard
Next step:
Add fused optim tests
Pull Request resolved: https://github.com/pytorch/pytorch/pull/99373
Approved by: https://github.com/mrshenli
