Move Arrays class to private library.

tests/language/list_test.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // 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.
 // Dart test program for testing arrays.
 
 class ListTest {
   static void TestIterator() {
     List<int> a = new List<int>(10);
     int count = 0;
 
@@ skipping 39 matching lines @@
     Expect.equals(1, a[1]);
     Expect.throws(() => a[len], (e) => e is RangeError);
 
     Expect.throws(() {
       List a = new List(4);
       a.setRange(1, 1, a, null);
     });
 
     Expect.throws(() {
       List a = new List(4);
+      a.setRange(1, 1, const [1, 2, 3, 4], null);
+    });
+
+    Expect.throws(() {
+      List a = new List(4);
       a.setRange(10, 1, a, 1);
     }, (e) => e is RangeError);
 
     a = new List(4);
     List b = new List(4);
     b.setRange(0, 4, a, 0);
 
     List<int> unsorted = [4, 3, 9, 12, -4, 9];
     int compare(a, b) {
       if (a < b) return -1;
@@ skipping 32 matching lines @@
     // We cannot write just 'list.removeLast' due to issue 3769.
     Expect.throws(() => list.removeLast(),
                   (e) => e is RangeError);
     Expect.equals(0, list.length);
   }
 }
 
 main() {
   ListTest.testMain();
 }