Reuse GlobalLayout in owner planning (#7966)

Signed-off-by: Jingyue Wu <jingyuew@nvidia.com>

Author: wujingyue

megatron/core/distributed/fsdp/src/megatron_fsdp/experimental/layout.py

@@ -31,15 +31,6 @@
 Shape: TypeAlias = torch.Size | Iterable[int]
 
 
-@dataclasses.dataclass(frozen=True)
-class TensorRange:
-    """Contiguous global element range occupied by one logical tensor."""
-
-    start: int
-    end: int
-    tensor_id: int
-
-
 @dataclasses.dataclass(frozen=True)
 class GlobalLayout:
     """Global tensor layout in element coordinates.