Fixes for AST summary generation when variables are missing.

pkg/analyzer/test/src/summary/in_summary_source_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 analyzer.test.src.summary.in_summary_source_test;
 
 import 'package:analyzer/src/generated/source_io.dart';
 import 'package:analyzer/src/summary/format.dart';
 import 'package:analyzer/src/summary/idl.dart';
 import 'package:analyzer/src/summary/package_bundle_reader.dart';
@@ skipping 53 matching lines @@
   factory MockSummaryDataStore.fake(Map<String, String> uriToSummary,
       {Map<String, String> uriToFallbackModePath: const {}}) {
     // Create fake unlinked map.
     // We don't populate the values as it is not needed for the test.
     var unlinkedMap = new Map<String, UnlinkedUnit>.fromIterable(
         uriToSummary.keys,
         value: (uri) => new UnlinkedUnitBuilder(
             fallbackModePath: uriToFallbackModePath[uri]));
     return new MockSummaryDataStore(null, unlinkedMap, uriToSummary);
   }
+
+  noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 }