simgrid: sleep while tasks and transfers are ongoing

We do not want to busily try to push transfers etc. and rather just
sleep until something happens.

src/drivers/cuda/driver_cuda.c

@@ -941,8 +941,7 @@ int _starpu_cuda_driver_run_once(struct _starpu_worker_set *worker_set)
 #endif
 
 	/* Something done, make some progress */
-	res = !idle_tasks || !idle_transfers;
-	res |= __starpu_datawizard_progress(1, 1);
+	res = __starpu_datawizard_progress(1, 1);
 
 	/* And pull tasks */
 	res |= _starpu_get_multi_worker_task(worker_set->workers, tasks, worker_set->nworkers, worker0->memory_node);

src/drivers/opencl/driver_opencl.c

@@ -792,8 +792,7 @@ int _starpu_opencl_driver_run_once(struct _starpu_worker *worker)
 	}
 #endif
 
-	res = !idle_tasks || !idle_transfers;
-	res |= __starpu_datawizard_progress(1, 1);
+	res = __starpu_datawizard_progress(1, 1);
 
 	task = _starpu_get_worker_task(worker, workerid, memnode);