Fix product build

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 305 matching lines @@
   Dart_ExitScope();
 }
 
 
 UNIT_TEST_CASE(CustomIsolates) {
   bool saved_flag = FLAG_trace_shutdown;
   FLAG_trace_shutdown = true;
   FLAG_verify_handles = true;
 #ifdef DEBUG
   FLAG_verify_on_transition = true;
-#endif
-  // Cannot verify heap while running compilation in background.
-  // Issue #26149.
+  // Cannot verify heap while running compilation in background. Issue #26149.
   FLAG_background_compilation = false;
   // Issue #26150.
   FLAG_use_osr = false;
-
+#endif
   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 21 matching lines @@
   OS::Print("-- Finished event loop --\n");
   EXPECT_STREQ("Received: 43", saved_echo);
   free(saved_echo);
 
   delete event_queue;
   event_queue = NULL;
   FLAG_trace_shutdown = saved_flag;
 }
 
 }  // namespace dart