[es6] Object.getPrototypeOf should work with values

test/webkit/prototypes.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions
 // are met:
 // 1.  Redistributions of source code must retain the above copyright
 //     notice, this list of conditions and the following disclaimer.
 // 2.  Redistributions in binary form must reproduce the above copyright
 //     notice, this list of conditions and the following disclaimer in the
@@ skipping 25 matching lines @@
 shouldBe("Array.prototype.__proto__", "Object.prototype");
 shouldBe("Date.prototype.__proto__", "Object.prototype");
 shouldBe("Number.prototype.__proto__", "Object.prototype");
 shouldBe("Object.prototype.__proto__", "null");
 shouldBe("String.prototype.__proto__", "Object.prototype");
 shouldBe("Array.__proto__", "Object.__proto__");
 shouldBe("Date.__proto__", "Object.__proto__");
 shouldBe("Number.__proto__", "Object.__proto__");
 shouldBe("String.__proto__", "Object.__proto__");
 
-shouldThrow("Object.getPrototypeOf('')");
-shouldThrow("Object.getPrototypeOf(0)");
+shouldBe("Object.getPrototypeOf('')", "String.prototype");
+shouldBe("Object.getPrototypeOf(0)", "Number.prototype");
 shouldBe("Object.getPrototypeOf([])", "Array.prototype");
 shouldBe("Object.getPrototypeOf({})", "Object.prototype");
 shouldBe("Object.getPrototypeOf(new Date)", "Date.prototype");
 shouldBe("Object.getPrototypeOf(new Number)", "Number.prototype");
 shouldBe("Object.getPrototypeOf(new Object)", "Object.prototype");
 shouldBe("Object.getPrototypeOf(new String)", "String.prototype");
 shouldBe("Object.getPrototypeOf(Array.prototype)", "Object.prototype");
 shouldBe("Object.getPrototypeOf(Date.prototype)", "Object.prototype");
 shouldBe("Object.getPrototypeOf(Number.prototype)", "Object.prototype");
 shouldBe("Object.getPrototypeOf(Object.prototype)", "null");
@@ skipping 24 matching lines @@
 shouldBeTrue("var wasSet = false; var o = { }; o.__defineSetter__(\"__proto__\", function() { wasSet = true }); o.__proto__ = {}; wasSet;");
 shouldBeTrue("var wasSet = false; var o = { }; Object.defineProperty(o, \"__proto__\", { \"get\": function() { wasSet = true } }); o.__proto__; wasSet;");
 shouldBeFalse("var wasSet = false; var o = { }; Object.defineProperty(o, \"__proto__\", { \"__proto__\": function(x) { wasSet = true } }); o.__proto__ = {}; wasSet;");
 
 // Deleting Object.prototype.__proto__ removes the ability to set the object's prototype.
 shouldBeTrue("var o = {}; o.__proto__ = { x:true }; o.x");
 shouldBeFalse("var o = {}; o.__proto__ = { x:true }; o.hasOwnProperty('__proto__')");
 delete Object.prototype.__proto__;
 shouldBeUndefined("var o = {}; o.__proto__ = { x:true }; o.x");
 shouldBeTrue("var o = {}; o.__proto__ = { x:true }; o.hasOwnProperty('__proto__')");