[VM generic functions] Disallow generic function types as type arguments or bounds.

tests/language_2/generic_methods_generic_function_result_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.
 //
 // VMOptions=--generic-method-syntax,--error-on-bad-type
 
-// Verify that function type parameter S can be resolved in bar.
+// Verify that function type parameter S can be resolved in bar's result type.
+// Verify that generic function types are not allowed as type arguments.
 
 import "package:expect/expect.dart";
 
-T foo<T extends num>(int i, T t) => i + t;
+int foo
+       <T>  //# 01: continued
+          (int i, int j) => i + j;
 
-List<T Function<T extends num>(S, T)> bar<S extends int>() {
-  return <T Function<T extends num>(S, T)>[foo, foo];
+List<int Function
+                 <T>  //# 01: compile-time error
+                    (S, int)> bar<S extends int>() {
+  return <int Function
+                      <T>  //# 01: continued
+                         (S, int)>[foo, foo];
 }
 
 void main() {
   var list = bar<int>();
-  print(list[0]
-      .runtimeType); // "<T extends num>(int, T) => T" when reifying generic functions.
+  print(list[0].runtimeType);
   Expect.equals(123, list[1]<int>(100, 23));
 }