Flatten the Arrays returned and consumed by the v8::Map API

src/collection.js

Index: src/collection.js
diff --git a/src/collection.js b/src/collection.js
index 1c6b475df6cf4761f4d25738150b1d3bfa3c44d5..86898529c3b7e8289e55b33696307c216eb3dfe5 100644
--- a/src/collection.js
+++ b/src/collection.js
@@ -485,9 +485,10 @@ $getExistingHash = GetExistingHash;
 $mapFromArray = function(array) {
   var map = new GlobalMap;
   var length = array.length;
-  for (var i = 0; i < length; ++i) {
-    var entry = array[i];
-    %_CallFunction(map, entry[0], entry[1], MapSet);
+  for (var i = 0; i < length; i += 2) {
+    var key = array[i];
+    var value = array[i + 1];
+    %_CallFunction(map, key, value, MapSet);
   }
   return map;
 };