Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/utf/utf.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.
+
+/**
+ * Support for encoding and decoding Unicode characters in UTF-8, UTF-16, and
+ * UTF-32.
+ */
+library utf;
+
+import "dart:async";
+import "dart:collection";
+
+import "src/constants.dart";
+import 'src/utf_16_code_unit_decoder.dart';
+import 'src/list_range.dart';
+import 'src/util.dart';
+
+export 'src/constants.dart';
+export 'src/utf_16_code_unit_decoder.dart';
+
+part "src/utf/utf_stream.dart";
+part "src/utf/utf8.dart";
+part "src/utf/utf16.dart";
+part "src/utf/utf32.dart";