Delete support for source mirrors

tests/compiler/dart2js/mirrors/relation_subtype_test.dart

Index: tests/compiler/dart2js/mirrors/relation_subtype_test.dart
diff --git a/tests/compiler/dart2js/mirrors/relation_subtype_test.dart b/tests/compiler/dart2js/mirrors/relation_subtype_test.dart
deleted file mode 100644
index 2fca90c20d34b635087688c998acce1e29edce6d..0000000000000000000000000000000000000000
--- a/tests/compiler/dart2js/mirrors/relation_subtype_test.dart
+++ /dev/null
@@ -1,17 +0,0 @@
-// 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 "dart:mirrors";
-
-import "package:async_helper/async_helper.dart";
-
-import "mirrors_test_helper.dart";
-import "../../../lib/mirrors/relation_subtype_test.dart";
-
-main() {
-  asyncTest(() => analyze("relation_subtype_test.dart").
-      then((MirrorSystem mirrors) {
-    test(mirrors);
-  }));
-}