Merge more Kernel infrastructure from kernel_sdk SDK fork.

tests/kernel/unsorted/super_mixin_test.dart

+import 'expect.dart';

[Kevin Millikin (Google), 2016/10/21 09:10:58]

Copyright header.

[Vyacheslav Egorov (Google), 2016/10/21 13:39:43]

Done.

+
+class Base {
+  var field;
+
+  method(x) {
+    print(x);
+    return x;
+  }
+
+  set setter(x) {
+    print(x);
+    field = x;
+  }
+}
+
+class Mixin {
+  method(x) {
+    return super.method(x + 'Mixin');
+  }
+
+  set setter(x) {
+    super.setter = x + 'Mixin';
+  }
+}
+
+class Sub extends Base with Mixin {
+}
+
+main() {
+  var object = new Sub();
+  Expect.isTrue(object.method('x') == 'xMixin');
+  object.setter = 'y';
+  Expect.isTrue(object.field == 'yMixin');
+}