Added back helper file accidentally deleted during test block 219 migration.

tests/lib_2/mirrors/delegate_function_invocation_test.dart

 // Copyright (c) 2014, 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.delgate_function_invocation;
 
 import 'dart:mirrors';
 
 import 'package:expect/expect.dart';
 
 class Proxy {
   var targetMirror;
   Proxy(target) : this.targetMirror = reflect(target);
   noSuchMethod(invocation) => targetMirror.delegate(invocation);
 }
 
 testClosure() {
-  var proxy = new Proxy(() => 42);
+  dynamic proxy = new Proxy(() => 42);
   Expect.equals(42, proxy());
   Expect.equals(42, proxy.call());
 }
 
 class FakeFunction {
   call() => 43;
 }
 
 testFakeFunction() {
-  var proxy = new Proxy(new FakeFunction());
+  dynamic proxy = new Proxy(new FakeFunction());
   Expect.equals(43, proxy());
   Expect.equals(43, proxy.call());
 }
 
 topLevelFunction() => 44;
 
 testTopLevelTearOff() {
-  var proxy = new Proxy(topLevelFunction);
+  dynamic proxy = new Proxy(topLevelFunction);
   Expect.equals(44, proxy());
   Expect.equals(44, proxy.call());
 }
 
 class C {
   method() => 45;
 }
 
 testInstanceTearOff() {
-  var proxy = new Proxy(new C().method);
+  dynamic proxy = new Proxy(new C().method);
   Expect.equals(45, proxy());
   Expect.equals(45, proxy.call());
 }
 
 main() {
   testClosure();
   testFakeFunction();
   testTopLevelTearOff();
   testInstanceTearOff();
 }