Implement Object.prototype.{hasOwnProperty, propertyIsEnumerable} for proxies.

src/proxy.js

Index: src/proxy.js
diff --git a/src/proxy.js b/src/proxy.js
index 27524bd91849ae8b880a676133c6184b3b41470b..28391595631e8877e39bae9fcefd62181b35433a 100644
--- a/src/proxy.js
+++ b/src/proxy.js
@@ -136,6 +136,10 @@ function DerivedHasTrap(name) {
   return !!this.getPropertyDescriptor(name)
 }
 
+function DerivedHasOwnTrap(name) {
+  return !!this.getOwnPropertyDescriptor(name)
+}
+
 function DerivedKeysTrap() {
   var names = this.getOwnPropertyNames()
   var enumerableNames = []