Fix debug and release builds.

runtime/lib/vmservice.cc

 // 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.
 
 #include "vm/bootstrap_natives.h"
 #include "vm/dart_api_impl.h"
 #include "vm/datastream.h"
 #include "vm/exceptions.h"
 #include "vm/flags.h"
 #include "vm/growable_array.h"
@@ skipping 468 matching lines @@
       Service::HandleEvent(&spawn_event);
     }
   } else {
     // The isolate failed to spawn.
     ASSERT(result.IsString());
     ServiceEvent spawn_event(NULL, ServiceEvent::kIsolateSpawn);
     spawn_event.set_spawn_token(&token);
     spawn_event.set_spawn_error(&String::Cast(result));
     Service::HandleEvent(&spawn_event);
   }
-#else
+#endif
   return Object::null();
-#endif
 }
 
 }  // namespace dart