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

runtime/observatory/tests/service/bad_web_socket_address_test.dart

 // Copyright (c) 2014, 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 'package:logging/logging.dart';
 import "package:observatory/service_io.dart";
 import 'package:unittest/unittest.dart';
 
 void testBadWebSocket() {
   var vm = new WebSocketVM(new WebSocketVMTarget('ws://karatekid/ws'));
   vm.load().catchError(expectAsync((error) {
     expect(error, new isInstanceOf<NetworkRpcException>());
   }));
 }
 
 main() {
   Logger.root.level = Level.INFO;
   Logger.root.onRecord.listen((LogRecord rec) {
     print('${rec.level.name}: ${rec.time}: ${rec.message}');
   });
 
   test('bad web socket address', testBadWebSocket);
 }