Don't crash on deserialized type inference.

tests/compiler/dart2js/serialization_resolved_ast_test.dart

 // Copyright (c) 2016, 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.serialization_resolved_ast_test;
 
 import 'dart:async';
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
 import 'package:compiler/src/commandline_options.dart';
@@ skipping 50 matching lines @@
 }
 
 void checkAllResolvedAsts(
     Compiler compiler1,
     Compiler compiler2,
     {bool verbose: false}) {
   checkLoadedLibraryMembers(
       compiler1,
       compiler2,
       (Element member1) {
-        return compiler1.resolution.hasResolvedAst(member1);
+        return member1 is ExecutableElement &&
+            compiler1.resolution.hasResolvedAst(member1);
       },
       checkResolvedAsts,
       verbose: verbose);
 }
 
 
 /// Check equivalence of [impact1] and [impact2].
 void checkResolvedAsts(Compiler compiler1, Element member1,
                        Compiler compiler2, Element member2,
                        {bool verbose: false}) {
   ResolvedAst resolvedAst1 = compiler1.resolution.getResolvedAst(member1);
   ResolvedAst resolvedAst2 =
       compiler2.serialization.deserializer.getResolvedAst(member2);
 
   if (resolvedAst1 == null || resolvedAst2 == null) return;
 
   if (verbose) {
     print('Checking resolved asts for $member1 vs $member2');
   }
 
   testResolvedAstEquivalence(
       resolvedAst1, resolvedAst2, const CheckStrategy());
 }