Make sure we don't do localhost transfers

src/core/simgrid.c

@@ -228,6 +228,7 @@ msg_task_t _starpu_simgrid_transfer_task_create(unsigned src_node, unsigned dst_
 
 	hosts[0] = _starpu_simgrid_memory_node_get_host(src_node);
 	hosts[1] = _starpu_simgrid_memory_node_get_host(dst_node);
+	STARPU_ASSERT(hosts[0] != hosts[1]);
 	communication[1] = size;
 
 	return MSG_parallel_task_create("copy", 2, hosts, computation, communication, NULL);