[builtins] Migrate Object.getOwnPropertyDescriptor to C++.

src/js/v8natives.js

Index: src/js/v8natives.js
diff --git a/src/js/v8natives.js b/src/js/v8natives.js
index c14f9f2f1fcbcb9c746d82cc74291ac2a1b399d4..3113aa76dccc33e1dbf074d1e35ca7db58aa48c6 100644
--- a/src/js/v8natives.js
+++ b/src/js/v8natives.js
@@ -772,12 +772,6 @@ function ObjectSetPrototypeOf(obj, proto) {
 }
 
 
-// ES6 section 19.1.2.6
-function ObjectGetOwnPropertyDescriptor(obj, p) {
-  return %GetOwnProperty(obj, p);
-}
-
-
 // ES5 section 15.2.3.6.
 function ObjectDefineProperty(obj, p, attributes) {
   // The new pure-C++ implementation doesn't support O.o.
@@ -877,7 +871,6 @@ utils.InstallFunctions(GlobalObject, DONT_ENUM, [
   "defineProperties", ObjectDefineProperties,
   "getPrototypeOf", ObjectGetPrototypeOf,
   "setPrototypeOf", ObjectSetPrototypeOf,
-  "getOwnPropertyDescriptor", ObjectGetOwnPropertyDescriptor,
   // getOwnPropertySymbols is added in symbol.js.
   "is", SameValue,  // ECMA-262, Edition 6, section 19.1.2.10
   // deliverChangeRecords, getNotifier, observe and unobserve are added