Build Observatory as part of runtime

runtime/observatory/test/functions_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.
 
 library functions_test;
 
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
 
@@ skipping 15 matching lines @@
       return fooClass.get('functions/get%3Aa').then((ServiceFunction func) {
         expect(func.name, equals('a'));
         expect(func.kind, equals(FunctionKind.kImplicitGetterFunction));
       });
     });
 }),
 
 ];
 
 main(args) => runIsolateTests(args, tests, testeeBefore: script);