Cleanup of messages.js.

Lock down some otherwise modifiable objects that don't need it.

Review URL: http://codereview.chromium.org/7828003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9089 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/math.js

@@ -38,7 +38,7 @@ const $abs = MathAbs;
 function MathConstructor() {}
 %FunctionSetInstanceClassName(MathConstructor, 'Math');
 const $Math = new MathConstructor();
-$Math.__proto__ = global.Object.prototype;
+$Math.__proto__ = $Object.prototype;
 %SetProperty(global, "Math", $Math, DONT_ENUM);
 
 // ECMA 262 - 15.8.2.1

src/runtime.js

@@ -48,6 +48,7 @@ const $Number = global.Number;
 const $Function = global.Function;
 const $Boolean = global.Boolean;
 const $NaN = 0/0;
+const builtins = this;
 
 // ECMA-262 Section 11.9.3.
 function EQUALS(y) {