test: terminate scheduler on timeout

CMK-20046

tests/test_scheduler.rs

@@ -358,6 +358,9 @@ async fn run_scheduler(
             bail!("Scheduler terminated unexpectedly")
         },
         _ = sleep(Duration::from_secs(n_seconds_run_max)) => {
+            if let Err(e) = remove_file(&run_flag_path) {
+                eprintln!("Removing run file failed: {e}");
+            }
             bail!(format!("Not all plan result files appeared within {n_seconds_run_max} seconds"))
         },
     };