Delete old tests that aren't used and/or useful any more.

tests/utils/dart2js_test.dart

Index: tests/utils/dart2js_test.dart
diff --git a/tests/utils/dart2js_test.dart b/tests/utils/dart2js_test.dart
deleted file mode 100644
index 51c5b12c64176d7d81e1074338d1cb5eaa5508ca..0000000000000000000000000000000000000000
--- a/tests/utils/dart2js_test.dart
+++ /dev/null
@@ -1,12 +0,0 @@
-// Copyright (c) 2012, 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.
-
-// Test to ensure that dart2js is free of warnings.
-
-// ignore: UNUSED_IMPORT
-import 'package:compiler/src/dart2js.dart' as dart2js;
-
-void main() {
-  // Do nothing.
-}