Manually close the tree for issue #88531 (#88532)

dev/devicelab/bin/tasks/hot_mode_dev_cycle_macos_target__benchmark.dart

@@ -3,8 +3,12 @@
 // found in the LICENSE file.
 
 import 'package:flutter_devicelab/framework/framework.dart';
+import 'package:flutter_devicelab/framework/task_result.dart';
 import 'package:flutter_devicelab/tasks/hot_mode_tests.dart';
 
 Future<void> main() async {
   await task(createHotModeTest(deviceIdOverride: 'macos'));
+  // TODO(zra): https://github.com/flutter/flutter/issues/88531
+  throw TaskResult.failure(
+      'Tree is manuall closed https://github.com/flutter/flutter/issues/88531');
 }