Revert of [es6] Object.getPrototypeOf should work with values

src/v8natives.js

Index: src/v8natives.js
diff --git a/src/v8natives.js b/src/v8natives.js
index c1af69a46928eb3a55d495898d4a8bfc64fb7569..4ba546b0fbca1765dd631af96f2c7ec0ef81759a 100644
--- a/src/v8natives.js
+++ b/src/v8natives.js
@@ -976,9 +976,12 @@
 }
 
 
-// ES6 section 19.1.2.9
+// ES5 section 15.2.3.2.
 function ObjectGetPrototypeOf(obj) {
-  return %_GetPrototype(TO_OBJECT_INLINE(obj));
+  if (!IS_SPEC_OBJECT(obj)) {
+    throw MakeTypeError("called_on_non_object", ["Object.getPrototypeOf"]);
+  }
+  return %_GetPrototype(obj);
 }
 
 // ES6 section 19.1.2.19.