Enable stub generation using Hydrogen/Lithium (again)

src/prettyprinter.cc

Index: src/prettyprinter.cc
diff --git a/src/prettyprinter.cc b/src/prettyprinter.cc
index 602fbb40b9840178da9da9c48c24483f72daa26f..c0fdf48ff1b8656541527eeda4c7d26806d38b05 100644
--- a/src/prettyprinter.cc
+++ b/src/prettyprinter.cc
@@ -42,6 +42,7 @@ PrettyPrinter::PrettyPrinter() {
   output_ = NULL;
   size_ = 0;
   pos_ = 0;
+  InitializeAstVisitor();
 }