Fix --verify_handles mode by properly checking for the static API handles.

runtime/vm/custom_isolate_test.cc

 // Copyright (c) 2011, 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 "include/dart_api.h"
 #include "include/dart_native_api.h"
 
 #include "vm/unit_test.h"
 
 // Custom Isolate Test.
@@ skipping 294 matching lines @@
   Dart_Handle send_port = Dart_NewSendPort(main_port_id);
   EXPECT_VALID(send_port);
   Dart_SetReturnValue(args, send_port);
 
   OS::Print("-- Exit: CustomIsolateImpl_start --\n");
   Dart_ExitScope();
 }
 
 
 UNIT_TEST_CASE(CustomIsolates) {
+  FLAG_verify_handles = true;
+  FLAG_verify_on_transition = true;
   event_queue = new EventQueue();
 
   Dart_Isolate dart_isolate = TestCase::CreateTestIsolate();
   EXPECT(dart_isolate != NULL);
   Dart_SetMessageNotifyCallback(&NotifyMessage);
   Dart_EnterScope();
   Dart_Handle result;
 
   // Create a test library.
   Dart_Handle lib = TestCase::LoadTestScript(kCustomIsolateScriptChars,
@@ skipping 19 matching lines @@
     event = event_queue->Get();
   }
   OS::Print("-- Finished event loop --\n");
   EXPECT_STREQ("Received: 43", saved_echo);
   free(const_cast<char*>(saved_echo));
 
   delete event_queue;
 }
 
 }  // namespace dart