Flush InterfaceTypeImpl cached memebers when ClassElement.version is different.

pkg/analyzer/lib/src/summary/link.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.
 
 /**
  * This library is capable of producing linked summaries from unlinked
  * ones (or prelinked ones).  It functions by building a miniature
  * element model to represent the contents of the summaries, and then
  * scanning the element model to gather linked information and adding
  * it to the summary data structures.
@@ skipping 575 matching lines @@
           _unnamedConstructor = constructor;
           break;
         }
       }
       _unnamedConstructorComputed = true;
     }
     return _unnamedConstructor;
   }
 
   @override
+  int get version => 0;
+
+  @override
   DartType buildType(
       DartType getTypeArgument(int i), List<int> implicitFunctionTypeIndices) {
     int numTypeParameters = _unlinkedClass.typeParameters.length;
     if (numTypeParameters != 0) {
       return new InterfaceTypeImpl.elementWithNameAndArgs(this, name, () {
         List<DartType> typeArguments = new List<DartType>(numTypeParameters);
         for (int i = 0; i < numTypeParameters; i++) {
           typeArguments[i] =
               getTypeArgument(i) ?? computeDefaultTypeArgument(i);
         }
@@ skipping 4347 matching lines @@
    * there are no type parameters in scope.
    */
   TypeParameterizedElementMixin get _typeParameterContext;
 
   @override
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 
   @override
   String toString() => '$enclosingElement.$name';
 }