partial fix for #25220, handles inference for list/map literals

pkg/analyzer/test/src/context/mock_sdk.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 analyzer.test.src.context.mock_sdk;
 
 import 'package:analyzer/file_system/file_system.dart' as resource;
 import 'package:analyzer/file_system/memory_file_system.dart' as resource;
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/context/context.dart';
@@ skipping 30 matching lines @@
   external factory String.fromCharCodes(Iterable<int> charCodes,
                                         [int start = 0, int end]);
   String operator +(String other) => null;
   bool get isEmpty => false;
   bool get isNotEmpty => false;
   int get length => 0;
   String substring(int len) => null;
   String toUpperCase();
   List<int> get codeUnits;
 }
+abstract class RegExp implements Pattern {
+  external factory RegExp(String source);
+}
 
 class bool extends Object {}
 abstract class num implements Comparable<num> {
   bool operator <(num other);
   bool operator <=(num other);
   bool operator >(num other);
   bool operator >=(num other);
   num operator +(num other);
   num operator -(num other);
   num operator *(num other);
@@ skipping 37 matching lines @@
 abstract class List<E> implements Iterable<E> {
   void add(E value);
   E operator [](int index);
   void operator []=(int index, E value);
   Iterator<E> get iterator => null;
   void clear();
 }
 
 abstract class Map<K, V> extends Object {
   Iterable<K> get keys;
+  V operator [](K key);
+  void operator []=(K key, V value);
 }
 
 external bool identical(Object a, Object b);
 
 void print(Object object) {}
 
 class _Override {
   const _Override();
 }
 const Object override = const _Override();
@@ skipping 247 matching lines @@
 
   @override
   AnalysisCache createCacheFromSourceFactory(SourceFactory factory) {
     if (factory == null) {
       return super.createCacheFromSourceFactory(factory);
     }
     return new AnalysisCache(
         <CachePartition>[AnalysisEngine.instance.partitionManager.forSdk(sdk)]);
   }
 }