Re-apply "Remove unittest and matcher from the repo."

pkg/matcher/lib/matcher.dart

Index: pkg/matcher/lib/matcher.dart
diff --git a/pkg/matcher/lib/matcher.dart b/pkg/matcher/lib/matcher.dart
deleted file mode 100644
index c7790c997ec612f14e0591bf6de26ad2cae417e3..0000000000000000000000000000000000000000
--- a/pkg/matcher/lib/matcher.dart
+++ /dev/null
@@ -1,22 +0,0 @@
-// Copyright (c) 2014, 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.
-
-/// Support for specifying test expectations, such as for unit tests.
-library matcher;
-
-export 'src/core_matchers.dart';
-export 'src/description.dart';
-export 'src/error_matchers.dart';
-export 'src/expect.dart';
-export 'src/future_matchers.dart';
-export 'src/interfaces.dart';
-export 'src/iterable_matchers.dart';
-export 'src/map_matchers.dart';
-export 'src/numeric_matchers.dart';
-export 'src/operator_matchers.dart';
-export 'src/prints_matcher.dart';
-export 'src/string_matchers.dart';
-export 'src/throws_matcher.dart';
-export 'src/throws_matchers.dart';
-export 'src/util.dart';