Fix %GetArrayKeys to not skip non-enumerable indices

test/mjsunit/array-unshift.js

Index: test/mjsunit/array-unshift.js
diff --git a/test/mjsunit/array-unshift.js b/test/mjsunit/array-unshift.js
index c4cc95cbb46f745203d62e472a07b688385b3d74..0ef44b71f29d260008c5c1f80b494f0ddb495a52 100644
--- a/test/mjsunit/array-unshift.js
+++ b/test/mjsunit/array-unshift.js
@@ -213,3 +213,18 @@
     assertEquals([1, 2, 3, 4, 5, 6, 7, 8, 9], a);
   }
 })();
+
+// Check that non-enumerable elements are treated appropriately
+(function() {
+  var array = [2, 3];
+  Object.defineProperty(array, '1', {enumerable: false});
+  array.unshift(1)
+  assertEquals([1, 2, 3], array);
+
+  array = [2];
+  array.length = 2;
+  array.__proto__[1] = 3;
+  Object.defineProperty(array.__proto__, '1', {enumerable: false});
+  array.unshift(1);
+  assertEquals([1, 2, 3], array);
+})();