Roll Observatory packages and add a roll script

packages/intl/lib/src/date_format_internal.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.
 
 /**
  * This contains internal implementation details of the date formatting code
  * which are exposed as public functions because they must be called by other
  * libraries in order to configure the source for the locale data. We don't want
  * them exposed as public API functions in the date formatting library, so they
  * are put in a separate library here. These are for internal use only. User
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  */
 void initializeDatePatterns(Function patterns) {
   if (dateTimePatterns is UninitializedLocaleData) {
     dateTimePatterns = patterns();
   }
 }
 
 Future initializeIndividualLocaleDateFormatting(Function init) {
   return init(dateTimeSymbols, dateTimePatterns);
 }