Small fixes to top level type inference.

pkg/front_end/testcases/inference/unsafe_block_closure_inference_function_call_explicit_type_param_via_expr2.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;
-
-List<T> f<T>(T g()) => <T>[g()];
-var /*@topType=dynamic*/ v = (f) /*@typeArgs=int*/ (/*@returnType=int*/ () {
-  return 1;
-});
-
-main() {
-  v;
-}