Handle resolvedAst for forwarding constructors and callType on unnamed mixin applications.

tests/compiler/dart2js/parser_test.dart

 // Copyright (c) 2011, 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.
 
 import "package:expect/expect.dart";
 import 'parser_helper.dart';
 import 'package:compiler/src/tree/tree.dart';
 
 void testStatement(String statement) {
   Node node = parseStatement(statement);
@@ skipping 301 matching lines @@
 
   void log(message) {
     print(message);
   }
 
   noSuchMethod(Invocation invocation) {
     throw 'unsupported operation';
   }
 
   @override
-  DiagnosticMessage createMessage(spannable, messageKind, [arguments]) {
+  DiagnosticMessage createMessage(
+      spannable, messageKind, [arguments = const {}]) {
     return new DiagnosticMessage(null, spannable, null);
   }
 }
 
 void testMissingCloseParen() {
   final String source =
 '''foo(x {  // <= missing closing ")"
   return x;
 }''';
   parse() {
@@ skipping 42 matching lines @@
   testConditionalExpression();
   testNullOperators();
   testAssignment();
   testIndex();
   testPostfix();
   testOperatorParse();
   testMissingCloseParen();
   testMissingCloseBraceInClass();
   testUnmatchedAngleBracket();
 }