Revert "Build Observatory with runtime"

runtime/bin/vmservice/observatory/lib/src/app/utils.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.
 
 part of app;
 
 class Utils {
   static String formatPercent(num a, num total) {
       var percent = 100.0 * (a / total);
       return '${percent.toStringAsFixed(2)}%';
@@ skipping 108 matching lines @@
     }
     return '${seconds}s';
   }
 
   static String formatSeconds(double x) {
     return x.toStringAsFixed(2);
   }
 
   static bool runningInJavaScript() => identical(1.0, 1);
 }