Format all tests.

tests/language_strong/body_less_constructor_wrong_arg_negative_test.dart

 // 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.
 
 main() {
   C o = const C(1);
 }
 
 class Base {
   final String name;
   const Base(this.name);
 }
 
 class C extends Base {
-  const C(var x): super(); // call super constructor with wrong argument count.
+  const C(var x) : super(); // call super constructor with wrong argument count.
 }