src: fix testEnumerables on ObjectWrap

PR-URL: #736
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

Author: fholzer

test/objectwrap.js

@@ -108,11 +108,15 @@ const test = (binding) => {
 keys.push(key);
 }
 
-assert(keys.length=4);
-assert(obj.testGetSet);
-assert(obj.testGetter);
-assert(obj.testValue);
-assert(obj.testMethod);
+assert(keys.length==6);
+// on prototype
+assert(keys.includes("testGetSet"));
+assert(keys.includes("testGetter"));
+assert(keys.includes("testValue"));
+assert(keys.includes("testMethod"));
+// on object only
+assert(keys.includes("ownProperty"));
+assert(keys.includes("ownPropertyT"));
 }
 };