Format all tests.

tests/language/regress_20840_test.dart

 // Copyright (c) 2014, 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.
 
 // Regression test for issue 20840.
 
 class SomeClass {
   Object someField;
 
   SomeClass() {
     [1].forEach((o) => someMethod());
     someField = new Object();
   }
 
   void someMethod() {
     if (someField != null) {
       throw "FAIL";
     }
   }
 }
 
 void main() {
   new SomeClass();
 }
-