Change test language/const_factory_negative_test.dart into a multi-test

tests/language/const_factory_negative_test.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.
-// For Dart VM: tests that a "const factory" with body produces an error.
-// For DartC: tests that a "const factory" is illegal.
-
-class ConstFactoryNegativeTest {
-  const factory ConstFactoryNegativeTest.one() {
-  }
-}
-
-main() {
-  const ConstFactoryNegativeTest.one();
-}