Fix 0.6.2 compatibility test shutdown

Stop and drop the old compatibility node from a blocking region.

This avoids a Tokio runtime-drop panic in the async test.

Co-Authored-By: HAL 9000

Author: tnull

tests/integration_tests_rust.rs

@@ -2580,7 +2580,11 @@ async fn build_0_6_2_node(
 	assert!(balance > 0);
 	let node_id = node_old.node_id();
 
-	node_old.stop().unwrap();
+	// Workaround necessary as v0.6.2's runtime wasn't dropsafe in a tokio context.
+	tokio::task::block_in_place(move || {
+		node_old.stop().unwrap();
+		drop(node_old);
+	});
 
 	(balance, node_id)
 }