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

runtime/observatory/tests/service/command_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 'package:observatory/cli.dart';
 import 'package:unittest/unittest.dart';
 
 class TestCommand extends Command {
   TestCommand(this.out, name, children) : super(name, children);
   StringBuffer out;
 
@@ skipping 204 matching lines @@
 
 main() {
   test('command completion test suite', testCommandComplete);
   test('run a simple command', testCommandRunSimple);
   test('run a subcommand', testCommandRunSubcommand);
   test('run a command which is not found', testCommandRunNotFound);
   test('run a command which is ambiguous', testCommandRunAmbiguous);
   test('run a command using an alias', testCommandRunAlias);
 }