Move Arrays, Collections and Maps into a new library, dart:collections.

runtime/lib/collections_sources.gypi

Index: runtime/lib/collections_sources.gypi
diff --git a/runtime/lib/scalarlist_sources.gypi b/runtime/lib/collections_sources.gypi
similarity index 68%
copy from runtime/lib/scalarlist_sources.gypi
copy to runtime/lib/collections_sources.gypi
index cb7c3ddd8f98026c38308515c96d38df7d944d63..37f15bf914bd7099afc55dd0a029d102ec9c2482 100644
--- a/runtime/lib/scalarlist_sources.gypi
+++ b/runtime/lib/collections_sources.gypi
@@ -2,12 +2,10 @@
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
-# Sources visible via dart:scalarlist library.
-
+# This file contains all sources for the dart:collections library.
 {
   'sources': [
-    'byte_array.cc',
-    'byte_array.dart',
+    '../../lib/collections/helpers.dart',
   ],
 }