Revert "Make window.{undefined,NaN,Infinity} read-only"

test/cctest/test-decls.cc

 // Copyright 2007-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 480 matching lines @@
 
 
 TEST(Reappearing) {
   HandleScope scope;
 
   { ReappearingPropertyContext context;
     context.Check("const x; var x = 0",
                   0,
                   2,  // var declaration + const initialization
                   4,  // 2 x declaration + 2 x initialization
-                  EXPECT_RESULT, Undefined());  // x = 0 fails for a const.
+                  EXPECT_EXCEPTION);  // x has already been declared!
   }
 }
 
 
 
 class ExistsInPrototypeContext: public DeclarationContext {
  protected:
   virtual v8::Handle<Integer> Query(Local<String> key) {
     // Let it seem that the property exists in the prototype object.
     return Integer::New(v8::None);
@@ skipping 72 matching lines @@
   HandleScope scope;
 
   { AbsentInPrototypeContext context;
     context.Check("if (false) { var x = 0; }; x",
                   0,
                   0,
                   1,  // declaration
                   EXPECT_RESULT, Undefined());
   }
 }