Fix dispatch name of covariance-checked calls.

pkg/kernel/lib/transformations/insert_covariance_checks.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 kernel.transformations.insert_covariance_checks;
 
 import '../class_hierarchy.dart';
 import '../clone.dart';
 import '../core_types.dart';
 import '../kernel.dart';
 import '../log.dart';
@@ skipping 486 matching lines @@
 
   @override
   visitLibrary(Library node) {
     if (!isTrustedLibrary(node)) {
       node.visitChildren(this);
     }
   }
 
   @override
   visitMethodInvocation(MethodInvocation node) {
-    node.interfaceTarget = getChecked(node.receiver, node.interfaceTarget);
+    var target = getChecked(node.receiver, node.interfaceTarget);
+    if (target != null) {
+      node.interfaceTarget = target;
+      node.name = target.name;
+    }
     node.visitChildren(this);
   }
 
   @override
   visitPropertySet(PropertySet node) {
-    node.interfaceTarget = getChecked(node.receiver, node.interfaceTarget);
+    var target = getChecked(node.receiver, node.interfaceTarget);
+    if (target != null) {
+      node.interfaceTarget = target;
+      node.name = target.name;
+    }
     node.visitChildren(this);
   }
 }