test rename overhaul: step 8 - language tests

tests/language/src/ConstObjectsAreImmutableTest.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.
-// Check that const objects (including literals) are immutable.
-
-class A {
-  const A(this.x, this.y);
-  final num x, y;
-}
-
-main() {
-  var list = const [1, 2];
-  Expect.throws(() => list[0] = 3);
-  Expect.equals(1, list[0]);
-
-  var m = const { 'foo': 499 };
-  Expect.throws(() => m['foo'] = 42);
-  Expect.equals(499, m['foo']);
-
-  var a1 = const A(1, 2);
-  Expect.throws(() => a1.x = 499);
-  Expect.equals(1, a1.x);
-
-  A a2 = const A(1, 2);
-  Expect.throws(() => a2.x = 499);
-  Expect.equals(1, a2.x);
-}