Remove most superfluous getter arguments from dart2js.

dart/lib/compiler/implementation/apiimpl.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.
 
 #library('leg_apiimpl');
 
 #import('dart:uri');
 
 #import('../compiler.dart', prefix: 'api');
 #import('leg.dart', prefix: 'leg');
@@ skipping 104 matching lines @@
     // [:span.uri:] might be [:null:] in case of a [Script] with no [uri]. For
     // instance in the [Types] constructor in typechecker.dart.
     if (span === null || span.uri === null) {
       handler(null, null, null, message, kind);
     } else {
       handler(translateUri(span.uri, null), span.begin, span.end,
               message, kind);
     }
   }
 
-  bool get isMockCompilation() {
+  bool get isMockCompilation {
     return mockableLibraryUsed
       && (options.indexOf('--allow-mock-compilation') !== -1);
   }
 }