Revert "Move `analyzer_cli` into the SDK."

pkg/analyzer_cli/test/data/super_mixin_example.dart

Index: pkg/analyzer_cli/test/data/super_mixin_example.dart
diff --git a/pkg/analyzer_cli/test/data/super_mixin_example.dart b/pkg/analyzer_cli/test/data/super_mixin_example.dart
deleted file mode 100644
index ea9048680fdecd48d5d63c715db8599fecb0a2fd..0000000000000000000000000000000000000000
--- a/pkg/analyzer_cli/test/data/super_mixin_example.dart
+++ /dev/null
@@ -1,18 +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.
-
-/// This produces errors normally, but --supermixin disables them.
-class Test extends Object with C {
-  void foo() {}
-}
-
-abstract class B {
-  void foo();
-}
-
-abstract class C extends B {
-  void bar() {
-    super.foo();
-  }
-}