test rename overhaul: step 8 - language tests

tests/language/src/Prefix2NegativeTest.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.
-//
-
-#library("Prefix2NegativeTest.dart");
-#import("library2.dart", prefix: "lib2");
-
-class Prefix2NegativeTest {
-  static Main() {
-    // This is a syntax error as multiple prefixes are not possible.
-    return lib2.Library2.main() + lib2.lib1.foo;
-  }
-}
-
-main() {
-  Prefix2NegativeTest.Main();
-}