Replace AddProperty by AddNamedProperty to speed up the common case

src/generator.js

Index: src/generator.js
diff --git a/src/generator.js b/src/generator.js
index 316ffa0f016c586c1817c57a719ad1bb3bf13ae7..54f6d8cd7e6a7d5e435b8a5f8be6a1b0a8008734 100644
--- a/src/generator.js
+++ b/src/generator.js
@@ -63,13 +63,13 @@ function SetUpGenerators() {
                    ["next", GeneratorObjectNext,
                     "throw", GeneratorObjectThrow]);
   %FunctionSetName(GeneratorObjectIterator, '[Symbol.iterator]');
-  %AddProperty(GeneratorObjectPrototype, symbolIterator,
+  %AddNamedProperty(GeneratorObjectPrototype, symbolIterator,
       GeneratorObjectIterator, DONT_ENUM | DONT_DELETE | READ_ONLY);
-  %AddProperty(GeneratorObjectPrototype, "constructor",
+  %AddNamedProperty(GeneratorObjectPrototype, "constructor",
       GeneratorFunctionPrototype, DONT_ENUM | DONT_DELETE | READ_ONLY);
   %SetPrototype(GeneratorFunctionPrototype, $Function.prototype);
   %SetCode(GeneratorFunctionPrototype, GeneratorFunctionPrototypeConstructor);
-  %AddProperty(GeneratorFunctionPrototype, "constructor",
+  %AddNamedProperty(GeneratorFunctionPrototype, "constructor",
       GeneratorFunction, DONT_ENUM | DONT_DELETE | READ_ONLY);
   %SetPrototype(GeneratorFunction, $Function);
   %SetCode(GeneratorFunction, GeneratorFunctionConstructor);