[DCP][Test]Remove broken 2d checkpoint test (#106640)
Summary: Removing this broken test as we are not going to land the fix for 2D regression. Instead, we are going to migrate to use device_mesh and dtensor state_dict for 2D.
Differential Revision: D48082586
Pull Request resolved: https://github.com/pytorch/pytorch/pull/106640
Approved by: https://github.com/fduwjj
