Handle creating ParameterMirrors for the parameters of forwarding constructors.

tests/lib/mirrors/immutable_collections_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.
 
 library test.immutable_collections;
 
 import 'dart:mirrors';
 import 'package:expect/expect.dart';
 
 someException(e) => e is Exception || e is Error;
@@ skipping 16 matching lines @@
 
 checkTypeVariable(TypeVariableMirror tvm) {
   checkList(tvm.metadata, 'TypeVariableMirror.metadata');
 }
 
 checkParameter(ParameterMirror pm) {
   checkList(pm.metadata, 'ParameterMirror.metadata');
 }
 
 checkMethod(MethodMirror mm) {
+  print(mm);
   checkList(mm.parameters, 'MethodMirror.parameters');
   checkList(mm.metadata, 'MethodMirror.metadata');
-
   mm.parameters.forEach(checkParameter);
 }
 
 checkClass(ClassMirror cm) {
   checkMap(cm.declarations, 'ClassMirror.declarations');
   checkMap(cm.instanceMembers, 'ClassMirror.instanceMembers');
   checkMap(cm.staticMembers, 'ClassMirror.staticMembers');
   checkList(cm.metadata, 'ClassMirror.metadata');
   checkList(cm.superinterfaces, 'ClassMirror.superinterfaces');
   checkList(cm.typeArguments, 'ClassMirror.typeArguments');
@@ skipping 22 matching lines @@
   checkList(lm.metadata, 'LibraryMirror.metadata');
 
   lm.declarations.values.forEach(checkDeclaration);
 }
 
 main() {
   currentMirrorSystem().libraries.values.forEach(checkLibrary);
   checkType(currentMirrorSystem().voidType);
   checkType(currentMirrorSystem().dynamicType);
 }