Roll Observatory packages and add a roll script

packages/analyzer/test/src/test_all.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.
+
+library test.src.test_all;
+
+import 'package:unittest/unittest.dart';
+
+import '../utils.dart';
+import 'context/test_all.dart' as context;
+import 'plugin/plugin_config_test.dart' as plugin;
+import 'task/test_all.dart' as task;
+import 'util/test_all.dart' as util;
+
+/// Utility for manually running all tests.
+main() {
+  initializeTestEnvironment();
+  group('src tests', () {
+    context.main();
+    plugin.main();
+    task.main();
+    util.main();
+  });
+}