Remove special list behavior in analysis server protocol.

pkg/analysis_server/lib/src/protocol.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 protocol;
 
 import 'dart:collection';
 import 'dart:convert';
 
 import 'package:analysis_server/src/computer/element.dart' show
@@ skipping 275 matching lines @@
     }
   }
   return null;
 }
 
 /**
  * Compare the lists [listA] and [listB], using [itemEqual] to compare
  * list elements.
  */
 bool _listEqual(List listA, List listB, bool itemEqual(a, b)) {
+  if (listA == null) {
+    return listB == null;
+  }
+  if (listB == null) {
+    return false;
+  }
   if (listA.length != listB.length) {
     return false;
   }
   for (int i = 0; i < listA.length; i++) {
     if (!itemEqual(listA[i], listB[i])) {
       return false;
     }
   }
   return true;
 }
@@ skipping 809 matching lines @@
     hash = 0x1fffffff & (hash + ((0x03ffffff & hash) << 3));
     hash = hash ^ (hash >> 11);
     return 0x1fffffff & (hash + ((0x00003fff & hash) << 15));
   }
 
   static int hash2(a, b) => finish(combine(combine(0, a), b));
 
   static int hash4(a, b, c, d) =>
       finish(combine(combine(combine(combine(0, a), b), c), d));
 }