[DTensor] Change Sharding algorithm to be in line with ``torch.chunk()`` (#98722)
As functional collective being updated, using tensor_split() as the underlying sharding algorithm would require padding and unpadding on multiple ranks. Therefore, we are changing the sharding algorithm to be in line with ``torch.chunk()`` to allow padding on the last two ranks in most of the scenarios.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/98722
Approved by: https://github.com/wanchaol
