Implement ParameterMirror.{isFinal,hasDefaultValue,defaultValue}.

tests/lib/mirrors/parameter_dart2js_test.dart

 // Copyright (c) 2013, 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 of [ParameterMirror].
 library test.parameter_test;
 
 @MirrorsUsed(targets: 'test.parameter_test', override: '*')
 import 'dart:mirrors';
 
@@ skipping 30 matching lines @@
   expect('[Parameter(s(z) in s(B.bar),'
          ' type = Class(s(int) in s(dart.core), top-level)), '
          'Parameter(s(x) in s(B.bar),'
          ' type = Type(s(dynamic), top-level))]',
          barConstructor.parameters);
   expect('Class(s(B) in s(test.parameter_test), top-level)',
          barConstructor.returnType);
 
   print(constructors);
 }