Move unittest tests underneath it in /pkg

pkg/unittest/tests/matchers_test.dart

 // Copyright (c) 2012, 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('matcherTest');
 #import('../../../pkg/unittest/unittest.dart');
 #source('test_utils.dart');
 
 doesNotThrow() {}
 doesThrow() { throw 'X'; }
@@ skipping 506 matching lines @@
 
   group('Predicate Matchers', () {
     test('isInstanceOf', () {
       shouldFail(0, predicate((x) => x is String, "an instance of String"),
         "Expected: an instance of String but: was <0>.");
       shouldPass('cow', predicate((x) => x is String, "an instance of String"));
     });
   });
 }