dart2js rti fix: functions are subtypes of Object

tests/language/function_subtype0_test.dart

 // Copyright (c) 2013, 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.
 // Dart test program for constructors and initializers.
 
 // Check function subtyping.
 
 import 'package:expect/expect.dart';
 
 typedef t__();
@@ skipping 18 matching lines @@
 void void_2() {}
 int int_() => 0;
 int int_2() => 0;
 Object Object_() => null;
 double double_() => 0.0;
 void void__int(int i) {}
 int int__int(int i) => 0;
 int int__int2(int i) => 0;
 int int__Object(Object o) => 0;
 Object Object__int(int i) => null;
+void void__Object(Object o) => null;
 int int__double(double d) => 0;
 int int__int_int(int i1, int i2) => 0;
 void inline_void_(void f()) {}
 void inline_void__int(void f(int i)) {}
 
 main() {
   // () -> int <: Function
   Expect.isTrue(int_ is Function);
   // () -> dynamic <: () -> dynamic
   Expect.isTrue(_ is t__);
@@ skipping 26 matching lines @@
   // (int) -> int <: (double) -> int
   Expect.isFalse(int__int is t_int__double);
   // () -> int <: (int) -> int
   Expect.isFalse(int_ is t_int__int);
   // (int) -> int <: (int,int) -> int
   Expect.isFalse(int__int is t_int__int_int);
   // (int,int) -> int <: (int) -> int
   Expect.isFalse(int__int_int is t_int__int);
   // (()->void) -> void <: ((int)->void) -> void
   Expect.isFalse(inline_void_ is t_inline_void__int);
+  // (Object) -> void <: ((int)->void) -> void
+  Expect.isTrue(void__Object is t_inline_void__int);
   // ((int)->void) -> void <: (()->void) -> void
   Expect.isFalse(inline_void__int is t_inline_void_);
 }