Generated front_end/testcases/inference test files from Analyzer tests.

pkg/front_end/testcases/inference/generic_methods_basic_downward_inference.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;
+
+T f<S, T>(S s) => null;
+main() {
+  String x = f(42);
+  String y = (f)(42);
+}