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

tests/language/const_factory_with_body_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.
 //
-// Test that a getter has no arguments
-get m(var extraParam) {
-  return null;
+// Tests that a "const factory" with body produces a compile-time error.
+
+class ConstFactoryWithBody {
+  const factory ConstFactoryWithBody.one() { }  /// 01: compile-time error
 }
 
 main() {
-  m;
+  const ConstFactoryWithBody.one();  /// 01: continued
 }
-