Fix observatory crash on most operations due to isolate not runnable

Source/bindings/core/dart/DartApplicationLoader.cpp

 // Copyright (c) 2009, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
@@ skipping 422 matching lines @@
                 Dart_FinalizeLoading(false);
                 Dart_Handle exception = 0;
                 JsInterop::buildInteropPatchFiles(DartDOMData::current(), &patches, exception);
                 if (exception) {
                     DartUtilities::reportProblem(m_originDocument, exception, m_scriptUrlString);
                 }
             }
             // TODO(jacobr): do we need to cleanup the dartDOMData for the isolate?
             Dart_ShutdownIsolate();
             free(script_snapshot);
-
+            Dart_IsolateMakeRunnable(applicationIsolate);
             Dart_EnterIsolate(applicationIsolate);
         }
 
         {
             Dart_Handle mainLibrary = topLevelLibrary();
 
             // Trampoline to invoke main.
             // FIXME: Use the page library instead. To do this, we need to import each script tag's library into the page
             // with a unique prefix to ensure a secondary script doesn't define a main.
             String trampolineUrl = m_scriptUrlString + "$trampoline";
@@ skipping 314 matching lines @@
 
 void DartApplicationLoader::reportError(const String& error, const String& url)
 {
     if (m_state < Running)
         m_state = Error;
     m_loadCallback->reportError(error, url);
 }
 
 
 }