Move all main methods to tool/.

pkg/front_end/lib/src/fasta/scanner/bin/scanner.dart

Index: pkg/front_end/lib/src/fasta/scanner/bin/scanner.dart
diff --git a/pkg/front_end/lib/src/fasta/scanner/bin/scanner.dart b/pkg/front_end/lib/src/fasta/scanner/bin/scanner.dart
deleted file mode 100644
index f31c42f6b8c0f0f5b88c9be0826028563d0fe485..0000000000000000000000000000000000000000
--- a/pkg/front_end/lib/src/fasta/scanner/bin/scanner.dart
+++ /dev/null
@@ -1,7 +0,0 @@
-// Copyright (c) 2016, 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 '../main.dart' as dart_scanner;
-
-main(List<String> arguments) => dart_scanner.main(arguments);