Improve messages and static use for super/this-calls.

tests/compiler/dart2js/memory_compiler.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 dart2js.test.memory_compiler;
 
 import 'dart:async';
 
 import 'package:compiler/compiler.dart' show
     DiagnosticHandler;
@@ skipping 22 matching lines @@
   final Message message;
   final Uri uri;
   final int begin;
   final int end;
   final String text;
   final Diagnostic kind;
 
   DiagnosticMessage(
       this.message, this.uri, this.begin, this.end, this.text, this.kind);
 
-  String toString() => '$uri:$begin:$end:$text:$kind';
+  String toString() => '${message.kind}:$uri:$begin:$end:$text:$kind';
 }
 
 class DiagnosticCollector implements CompilerDiagnostics {
   List<DiagnosticMessage> messages = <DiagnosticMessage>[];
 
   void call(Uri uri, int begin, int end, String message, Diagnostic kind) {
     report(null, uri, begin, end, message, kind);
   }
 
   @override
@@ skipping 276 matching lines @@
       createDiagnosticHandler(diagnosticHandler, provider, showDiagnostics);
 
   List<Uri> libraries = <Uri>[];
   memorySourceFiles.forEach((String path, _) {
     libraries.add(new Uri(scheme: 'memory', path: path));
   });
 
   return analyze(libraries, libraryRoot, packageRoot,
                  provider, handler, options);
 }