Fix observatory tests broken by running dartfmt. Temporarily reverted formatting for evaluate_activ…

runtime/observatory/tests/observatory_ui/mocks/objects/unknown.dart

 // Copyright (c) 2016, 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.
 
 part of mocks;
 
 class UnknownObjectRefMock implements M.UnknownObjectRef {
   final String id;
   final String vmType;
-  const UnknownObjectRefMock({this.id: 'literal-token-id',
-                              this.vmType: 'vmType'});
+  const UnknownObjectRefMock(
+      {this.id: 'literal-token-id', this.vmType: 'vmType'});
 }