Resolve signature from correct scope class (fix #25609).

tests/language/regress_25609_lib1.dart

Index: tests/language/regress_25609_lib1.dart
diff --git a/pkg/analyzer_cli/test/data/package_with_embedder_yaml/lib/async.dart b/tests/language/regress_25609_lib1.dart
similarity index 71%
copy from pkg/analyzer_cli/test/data/package_with_embedder_yaml/lib/async.dart
copy to tests/language/regress_25609_lib1.dart
index 3b69a2a4dca3f7b1454b5127c2e71c561a8ff496..98fdb207d90e4ceda60a2078ee301a25e6fb6f89 100644
--- a/pkg/analyzer_cli/test/data/package_with_embedder_yaml/lib/async.dart
+++ b/tests/language/regress_25609_lib1.dart
@@ -2,8 +2,9 @@
 // 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 dart.async;
+library regress_25609_lib1;
 
-abstract class Future<T> {}
+import 'regress_25609_lib2.dart';
+
+typedef Bar Foo(int y);
 
-abstract class Stream<T> {}