Make sure the signature of the call method is finalized before involving it

tests/language/regress_29025_test.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.
+
+typedef T F<T>(T t);
+
+class B<T extends F<T>> {}
+class C<T extends F<C<T>>> {}
+
+class D extends B<D> {
+  D foo(D x) => x;
+  D call(D x) => x;
+  D bar(D x) => x;
+}
+
+class E extends C<E> {
+  C<E> foo(C<E> x) => x;
+  C<E> call(C<E> x) => x;
+  C<E> bar(C<E> x) => x;
+}
+
+main() {
+ F<D> fd = new D();
+ var d = fd(fd);
+ print(d);
+ F<E> fe = new E();
+ var e = fe(fe);
+ print(e);
+}