[Arguments] Remove synthetic properties and all code dealing with them.

arguments/src/prettyprinter.cc

Index: arguments/src/prettyprinter.cc
diff --git a/arguments/src/prettyprinter.cc b/arguments/src/prettyprinter.cc
index dda7abbb3f6de1641abaf27a76f0c5c13e969960..c11d5e0703de6353e34a9bd38518daf798fa5661 100644
--- a/arguments/src/prettyprinter.cc
+++ b/arguments/src/prettyprinter.cc
@@ -1427,10 +1427,6 @@ void JsonAstBuilder::VisitThrow(Throw* expr) {
 
 void JsonAstBuilder::VisitProperty(Property* expr) {
   TagScope tag(this, "Property");
-  {
-    AttributesScope attributes(this);
-    AddAttribute("type", expr->is_synthetic() ? "SYNTHETIC" : "NORMAL");
-  }
   Visit(expr->obj());
   Visit(expr->key());
 }