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

runtime/observatory/tests/service/debugger_inspect_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 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
 import 'dart:async';
 import 'dart:developer';
 
 class Point {
   int x, y;
   Point(this.x, this.y);
@@ skipping 18 matching lines @@
   });
 
   // Start listening for events first.
   await isolate.rootLibrary.evaluate('testeeDo();');
   return completer.future;
 },
 
 ];
 
 main(args) => runIsolateTests(args, tests);