Removes unnecessary call to `purge_old_bank_snapshots()` in local-cluster test (#32111)

local-cluster/tests/local_cluster.rs

@@ -1108,14 +1108,6 @@ fn test_incremental_snapshot_download_with_crossing_full_snapshot_interval_at_st
     info!(
         "Restarting the validator with full snapshot {validator_full_snapshot_slot_at_startup}..."
     );
-    // To restart, it is not enough to remove the old bank snapshot directories under snapshot/.
-    // The old hardlinks under <account_path>/snapshot/<slot> should also be removed.
-    // The purge call covers all of them.
-    snapshot_utils::purge_old_bank_snapshots(
-        validator_snapshot_test_config.bank_snapshots_dir,
-        0,
-        None,
-    );
     cluster.restart_node(
         &validator_identity.pubkey(),
         validator_info,