Support use of dill in TypeEnv tests

tests/compiler/dart2js/members_test.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 members_test;
 
 import 'package:expect/expect.dart';
 import "package:async_helper/async_helper.dart";
 import 'type_test_helper.dart';
 import 'package:compiler/src/elements/resolution_types.dart';
@@ skipping 169 matching lines @@
     }
     class B<T> {
       T field;
       void method(T t) {}
       static staticMethod() {}
       toString([T t]) {}
     }
     class C<S> extends B<S> {}
     class D extends C<int> {}
     class E extends D {}
-    """, useMockCompiler: false).then((env) {
+    """, compileMode: CompileMode.memory).then((env) {
         ResolutionInterfaceType bool_ = env['bool'];
         ResolutionInterfaceType String_ = env['String'];
         ResolutionInterfaceType int_ = env['int'];
         ResolutionDynamicType dynamic_ = env['dynamic'];
         ResolutionVoidType void_ = env['void'];
         ResolutionInterfaceType Type_ = env['Type'];
         ResolutionInterfaceType Invocation_ = env['Invocation'];
 
         ResolutionInterfaceType Object_ = env['Object'];
         checkMemberCount(Object_, 5 /*declared*/, interfaceMembers: true);
@@ skipping 541 matching lines @@
 
         // Ensure that members have been computed on all classes.
         MembersCreator.computeAllClassMembers(env.resolution, C.element);
 
         checkMember(C, 'm',
             checkType: NO_CLASS_MEMBER,
             inheritedFrom: A,
             functionType: env.functionType(dynamic_, []));
       }));
 }