Fix --compile_all flag (--compile-all is wrong)

runtime/observatory/tests/service/isolate_lifecycle_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
-// VMOptions=--compile-all --error_on_bad_type --error_on_bad_override
+// VMOptions=--compile_all --error_on_bad_type --error_on_bad_override
 
 import 'dart:async';
 import 'dart:isolate' as I;
 
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 
 import 'test_helper.dart';
 
 final spawnCount = 4;
@@ skipping 109 matching lines @@
   (VM vm) async {
     expect(numPaused(vm), spawnCount - resumeCount);
     expect(numRunning(vm), 1);
   },
 ];
 
 main(args) async => runVMTests(args, tests,
                                testeeBefore: before,
                                testeeConcurrent: during,
                                pause_on_exit: true);