upgrade dependencies, including migration to package:test

test/runtime/dart_logging_runtime_test.dart

 // 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.
 
 import 'package:dev_compiler/runtime/dart_logging_runtime.dart' as devc;
-import 'package:unittest/unittest.dart';
+import 'package:test/test.dart';
 
 class A<T> {
   T x;
   A(this.x);
 }
 
 class B extends A<String> {
   B() : super("B!");
 }
 
@@ skipping 31 matching lines @@
     int dartFailures = 0;
     devc.castRecordHandler = (String key, devc.CastRecord record) {
       devcFailures += record.soundCast ? 0 : 1;
       dartFailures += record.dartCast ? 0 : 1;
     };
     runTest();
     expect(devcFailures, equals(2));
     expect(dartFailures, equals(1));
   });
 }