Improve VM connection flow in Observatory

runtime/observatory/lib/src/repositories/isolate.dart

 // Copyright (c) 2016, 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 repositories;
 
 class IsolateRepository extends M.IsolateRepository {
   Future<M.Isolate> get(M.IsolateRef i) async{
     S.Isolate isolate = i as S.Isolate;
     assert(isolate != null);
-    await isolate.reload();
+    try {
+      await isolate.reload();
+    } on SC.NetworkRpcException catch (_) {
+      /* ignore */
+    }
     return isolate;
   }
 
   Future reloadSources(M.IsolateRef i) async{
     S.Isolate isolate = i as S.Isolate;
     assert(isolate != null);
     await isolate.reloadSources();
   }
 }