Remove dart backend

test/dart_codegen/types/d.dart

Index: test/dart_codegen/types/d.dart
diff --git a/test/dart_codegen/types/d.dart b/test/dart_codegen/types/d.dart
deleted file mode 100644
index 1333de0741dab5d1e5310c3cf0b3fb3b1ba9d3dd..0000000000000000000000000000000000000000
--- a/test/dart_codegen/types/d.dart
+++ /dev/null
@@ -1,13 +0,0 @@
-// Copyright (c) 2015, 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.
-
-library d;
-
-import 'b.dart';
-
-void foo() {
-  var x = f3(f4("""hello"""));
-  var y = f1(f4);
-  var z = f2(f3);
-}