Revert "Native mixin interceptor bug fix"

tests/compiler/dart2js_extra/10216a_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.
-
-import "package:expect/expect.dart";
-
-// Tests codegen of methods reached only via mixin.
-
-class A  {
-  foo(x, [y]) => '$x;$y';
-}
-
-class B extends A with M1, M2, M3 {
-}
-
-class M1 {}
-
-class M2 {
-  // These methods are only defined in this non-first, non-last mixin.
-  plain(x) => 'P $x';
-  // Check arity stubs are also available.
-  bar(x, [y]) => '$y,$x';
-}
-
-class M3 {}
-
-makeB() {
-  return [new A(), new B()].last as B;
-}
-
-main() {
-  // makeB enters the compilation worklist after main, so the selectors are
-  // registered before the classes.
-  var b = makeB();
-  Expect.equals('1;2', b.foo(1,2));
-  Expect.equals('2;null', b.foo(2));
-  Expect.equals('P 3', b.plain(3));
-  Expect.equals('100,4', b.bar(4,100));
-  Expect.equals('null,5', b.bar(5));
-}