Replace AddProperty by AddNamedProperty to speed up the common case

src/regexp.js

Index: src/regexp.js
diff --git a/src/regexp.js b/src/regexp.js
index 556ca37ac65c906ec901048bb59ef16d1887abd6..d7883fb693731769457836b5472af1e7637b854f 100644
--- a/src/regexp.js
+++ b/src/regexp.js
@@ -381,7 +381,7 @@ var lastMatchInfoOverride = null;
 function SetUpRegExp() {
   %CheckIsBootstrapping();
   %FunctionSetInstanceClassName($RegExp, 'RegExp');
-  %AddProperty($RegExp.prototype, 'constructor', $RegExp, DONT_ENUM);
+  %AddNamedProperty($RegExp.prototype, 'constructor', $RegExp, DONT_ENUM);
   %SetCode($RegExp, RegExpConstructor);
 
   InstallFunctions($RegExp.prototype, DONT_ENUM, $Array(