Record method invocation targets that are not procedures.

pkg/front_end/testcases/inference/future_union_downwards_generic_method_with_future_return.dart

 // Copyright (c) 2017, 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.
 
 /*@testedFeatures=inference*/
 library test;
 
 import 'dart:async';
 
 foo() async {
   Future<List<A>> f1 = null;
   Future<List<A>> f2 = null;
-  List<List<A>> merged =
-      await Future. /*@typeArgs=List<A>*/ /*@target=Future::wait*/ wait(
-          /*@typeArgs=Future<List<A>>*/ [f1, f2]);
+  List<List<A>> merged = await Future. /*@typeArgs=List<A>*/ wait(
+      /*@typeArgs=Future<List<A>>*/ [f1, f2]);
 }
 
 class A {}
 
 main() {}