Migrate test block 7 to Dart 2.0.

tests/corelib_strong/double_truncate2_test.dart

Index: tests/corelib_strong/double_truncate2_test.dart
diff --git a/tests/corelib_strong/double_truncate2_test.dart b/tests/corelib_strong/double_truncate2_test.dart
deleted file mode 100644
index 633debd61a467977caa53c666b35561c8b45eff2..0000000000000000000000000000000000000000
--- a/tests/corelib_strong/double_truncate2_test.dart
+++ /dev/null
@@ -1,12 +0,0 @@
-// 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() {
-  Expect.throws(() => double.INFINITY.truncate(), (e) => e is UnsupportedError);
-  Expect.throws(
-      () => double.NEGATIVE_INFINITY.truncate(), (e) => e is UnsupportedError);
-  Expect.throws(() => double.NAN.truncate(), (e) => e is UnsupportedError);
-}