delete observe from the repo

pkg/observe/test/observe_test_utils.dart

-// Copyright (c) 2013, 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 observe.test.observe_test_utils;
-
-import 'dart:async';
-import 'package:observe/observe.dart';
-import 'package:observe/mirrors_used.dart'; // to make tests smaller
-import 'package:unittest/unittest.dart';
-export 'package:observe/src/dirty_check.dart' show dirtyCheckZone;
-
-/// A small method to help readability. Used to cause the next "then" in a chain
-/// to happen in the next microtask:
-///
-///     future.then(newMicrotask).then(...)
-newMicrotask(_) => new Future.value();
-
-// TODO(jmesserly): use matchers when we have a way to compare ChangeRecords.
-// For now just use the toString.
-expectChanges(actual, expected, {reason}) =>
-    expect('$actual', '$expected', reason: reason);
-
-List getListChangeRecords(List changes, int index) => changes
-    .where((c) => c.indexChanged(index)).toList();
-
-List getPropertyChangeRecords(List changes, Symbol property) => changes
-    .where((c) => c is PropertyChangeRecord && c.name == property).toList();