Revert "[PTD][Checkpoint] Add checkpointing support for DTensor submesh (#96802)"
This reverts commit cfa6b52e02eb61f71c0034d5b7e73e365420f35a.
Reverted https://github.com/pytorch/pytorch/pull/96802 on behalf of https://github.com/huydhn due to This breaks distributed test https://hud.pytorch.org/pytorch/pytorch/commit/cfa6b52e02eb61f71c0034d5b7e73e365420f35a. Probably a landrace as PR signal was green
