Improve error message for assertion on replicated entries (#164)

Summary:
Pull Request resolved: #164

As title, report the mismatched paths in the error message to make it easier to debug

Reviewed By: RdoubleA, williamhufb

Differential Revision: D50896542

fbshipit-source-id: cc9d69c13c2313490b65bc4d30752a7e1c399ea9

torchsnapshot/partitioner.py

@@ -342,7 +342,10 @@ def consolidate_replicated_entries(
             if not is_fully_replicated_entry(entry):
                 continue
             if logical_path in replicated_entries:
-                assert replicated_entries[logical_path] == entry
+                if replicated_entries[logical_path] != entry:
+                    raise ValueError(
+                        f"Paths for replicated entry do not match: replicated entries={replicated_entries[logical_path]} vs. entry={entry}"
+                    )
             else:
                 replicated_entries[logical_path] = entry
             del entries[logical_path]