Revert "Merge more Kernel infrastructure from kernel_sdk SDK fork."

tests/kernel/unsorted/mixin_test.dart

-// Copyright (c) 2016, 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 'expect.dart';
-
-class Base {
-  baseFoo() {
-    print('Base.baseFoo()');
-    return 1;
-  }
-
-  foo() {
-    print('Base.foo()');
-    return 1;
-  }
-}
-
-class Mixin {
-  mixinFoo() {
-    print('Mixin.mixinFoo()');
-    return 2;
-  }
-
-  foo() {
-    print('Mixin.foo()');
-    return 2;
-  }
-}
-
-class Mixin2 {
-  mixin2Foo() {
-    print('Mixin2.mixin2Foo()');
-    return 3;
-  }
-
-  foo() {
-    print('Mixin2.foo()');
-    return 3;
-  }
-}
-
-class Sub extends Base with Mixin, Mixin2 {
-  subFoo() {
-    print('Sub.subFoo()');
-    return 4;
-  }
-
-  foo() {
-    print('Sub.foo()');
-    return 4;
-  }
-}
-
-main() {
-  var o = new Sub();
-
-  Expect.isTrue(o.baseFoo() == 1);
-  Expect.isTrue(o.mixinFoo() == 2);
-  Expect.isTrue(o.mixin2Foo() == 3);
-  Expect.isTrue(o.subFoo() == 4);
-  Expect.isTrue(o.foo() == 4);
-}
-