Abandon type inference on closures that (potentially) flow into Function.apply.

tests/compiler/dart2js/simple_inferrer_const_closure_default_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.
 
 import 'package:expect/expect.dart';
 import "package:async_helper/async_helper.dart";
 import 'compiler_helper.dart';
 import 'type_mask_test_helper.dart';
 
 
@@ skipping 53 matching lines @@
       var element = signature.optionalParameters.first;
       Expect.equals(type,
           simplify(typesInferrer.getTypeOfElement(element), compiler),
           functionName);
     }
 
     checkArgument('foo1', compiler.typesTask.functionType);   /// 01: ok
     checkArgument('foo2', compiler.typesTask.functionType);   /// 02: ok
     checkArgument('foo3', compiler.typesTask.functionType);   /// 03: ok
     checkArgument('foo4', compiler.typesTask.functionType);   /// 04: ok
-    checkArgument('foo5', compiler.typesTask.functionType);   /// 05: ok
-    checkArgument('foo6', compiler.typesTask.functionType);   /// 06: ok
+    checkArgument('foo5', compiler.typesTask.dynamicType);    /// 05: ok
+    checkArgument('foo6', compiler.typesTask.dynamicType);    /// 06: ok
 
     checkArgument('defaultFn1', compiler.typesTask.uint31Type);   /// 07: ok
     checkArgument('defaultFn2', compiler.typesTask.uint31Type);   /// 08: ok
     checkArgument('defaultFn3', compiler.typesTask.uint31Type);   /// 09: ok
     checkArgument('defaultFn4', compiler.typesTask.uint31Type);   /// 10: ok
     checkArgument('defaultFn5', compiler.typesTask.uint31Type);   /// 11: ok
     checkArgument('defaultFn6', compiler.typesTask.uint31Type);   /// 12: ok
   }));
 }