Add Shell::PrintErr and expose it in the d8 shell as printErr

src/d8.h

Index: src/d8.h
diff --git a/src/d8.h b/src/d8.h
index 16de77d570f682c6824af2f9fb94d9dfa735716f..5e7abafb0462fe418ea71aa600c77a192d2f358e 100644
--- a/src/d8.h
+++ b/src/d8.h
@@ -372,6 +372,7 @@ class Shell : public i::AllStatic {
                              const  PropertyCallbackInfo<void>& info);
 
   static void Print(const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void PrintErr(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void Write(const v8::FunctionCallbackInfo<v8::Value>& args);
   static void QuitOnce(v8::FunctionCallbackInfo<v8::Value>* args);
   static void Quit(const v8::FunctionCallbackInfo<v8::Value>& args);