Migrating another batch of tests to dart 2.

tests/language_strong/compile_time_constant12_test.dart

Index: tests/language_strong/compile_time_constant12_test.dart
diff --git a/tests/language_strong/compile_time_constant12_test.dart b/tests/language_strong/compile_time_constant12_test.dart
deleted file mode 100644
index 0acf8b05e0ba090ac796de8010e430ce8d0246f4..0000000000000000000000000000000000000000
--- a/tests/language_strong/compile_time_constant12_test.dart
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright (c) 2012, 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.
-
-const String s = "foo";
-const int i = s.length;
-const int l = "foo".length + 1;
-
-use(x) => x;
-
-main() {
-  use(s);
-  use(i);
-  use(l);
-}