Import rasta tests.

pkg/fasta/test/rasta/issue_000026.dart

+// Copyright (c) 2016, 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.md file.
+
+class C {
+  var a;
+  var b = 0;
+  var c = 1 + 2;
+}
+
+class D {
+  var a;
+  var b = 1;
+  var c = 2 - 3;
+  D();
+}
+
+main() {
+  new C();
+  new D();
+}