[mta][foreach] Implement fused adamw (#88015)
related: https://github.com/pytorch/pytorch/issues/68041, https://github.com/pytorch/pytorch/issues/71274, https://github.com/pytorch/pytorch/issues/80167
possibly related to https://github.com/pytorch/pytorch/issues/80595#issuecomment-1178519436
Pull Request resolved: https://github.com/pytorch/pytorch/pull/88015
Approved by: https://github.com/albanD, https://github.com/ngimel
