Migrate test block 11 to Dart 2.0.

tests/corelib/iterable_mapping_test.dart

-// Copyright (c) 2013, 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.
-
-import "package:expect/expect.dart";
-
-main() {
-  List<int> list1 = <int>[1, 2, 3];
-  List<int> list2 = const <int>[4, 5];
-  List<String> list3 = <String>[];
-  Set<int> set1 = new Set<int>();
-  set1.addAll([11, 12, 13]);
-  Set set2 = new Set();
-
-  Iterable mapped = list1.map((x) => x + 1);
-  Expect.listEquals([2, 3, 4], mapped.toList());
-
-  mapped = mapped.map((x) => x + 1);
-  Expect.listEquals([3, 4, 5], mapped.toList());
-
-  mapped = list2.map((x) => x + 1);
-  Expect.listEquals([5, 6], mapped.toList());
-
-  mapped = mapped.map((x) => x + 1);
-  Expect.listEquals([6, 7], mapped.toList());
-
-  mapped = list3.map((x) => x + 1);
-  Expect.listEquals([], mapped.toList());
-
-  mapped = mapped.map((x) => x + 1);
-  Expect.listEquals([], mapped.toList());
-
-  var expected = new Set<int>()..addAll([12, 13, 14]);
-  mapped = set1.map((x) => x + 1);
-  Expect.isFalse(mapped is List);
-  Expect.setEquals(expected, mapped.toSet());
-
-  expected = new Set<int>()..addAll([13, 14, 15]);
-  mapped = mapped.map((x) => x + 1);
-  Expect.isFalse(mapped is List);
-  Expect.setEquals(expected, mapped.toSet());
-
-  mapped = set2.map((x) => x + 1);
-  Expect.isFalse(mapped is List);
-  Expect.listEquals([], mapped.toList());
-
-  mapped = mapped.map((x) => x + 1);
-  Expect.isFalse(mapped is List);
-  Expect.listEquals([], mapped.toList());
-}