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

tests/kernel/unsorted/return_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.
-
-// Tests of return (and imports, literals, ==, and static methods).
-
-import 'expect.dart';
-
-test0() {}
-
-test1() { return; }
-
-test3() { return 3; }
-
-test4() => 4;
-
-test5() {
-  return 5;
-  Expect.isTrue(false);
-}
-
-main() {
-  Expect.isTrue(test0() == null);
-  Expect.isTrue(test1() == null);
-  Expect.isTrue(test3() == 3);
-  Expect.isTrue(test4() == 4);
-  Expect.isTrue(test5() == 5);
-}