Revert "First step for modular output in fasta."

pkg/front_end/testcases/shaker/roots0.dart

Index: pkg/front_end/testcases/shaker/roots0.dart
diff --git a/pkg/front_end/testcases/shaker/roots0.dart b/pkg/front_end/testcases/shaker/roots0.dart
deleted file mode 100644
index 3a3c44666d77a3967d55f0978f07a3393ee0de22..0000000000000000000000000000000000000000
--- a/pkg/front_end/testcases/shaker/roots0.dart
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright (c) 2017, 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.md file.
-
-import 'lib/lib.dart';
-
-/// Tree-shaker preserves APIs used anywhere in the library, there is no special
-/// root, and `main` is no special.
-main() => toplevel();