Change DateTime.parse FormatException messages; update tests

sdk/lib/core/date_time.dart

 // Copyright (c) 2011, 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.
 
 part of dart.core;
 
 /**
  * An instant in time, such as July 20, 1969, 8:18pm GMT.
  *
  * Create a DateTime object by using one of the constructors
@@ skipping 221 matching lines @@
      * time_opt ::= <empty> | (' ' | 'T') hour minutes_opt
      * minutes_opt ::= <empty> | ':' digit{2} seconds_opt
      * seconds_opt ::= <empty> | ':' digit{2} millis_opt
      * millis_opt ::= <empty> | '.' digit{1,6}
      * timezone_opt ::= <empty> | space_opt timezone
      * space_opt :: ' ' | <empty>
      * timezone ::= 'z' | 'Z' | sign digit{2} timezonemins_opt
      * timezonemins_opt ::= <empty> | colon_opt digit{2}
      */
     final RegExp re = new RegExp(
-        r'^([+-]?\d{4,5})-?(\d\d)-?(\d\d)'  // The day part.
+        r'^([+-]?\d{4,6})-?(\d\d)-?(\d\d)'  // The day part.
         r'(?:[ T](\d\d)(?::?(\d\d)(?::?(\d\d)(.\d{1,6})?)?)?' // The time part
         r'( ?[zZ]| ?([-+])(\d\d)(?::?(\d\d))?)?)?$'); // The timezone part
 
     Match match = re.firstMatch(formattedString);
     if (match != null) {
       int parseIntOrZero(String matched) {
         if (matched == null) return 0;
         return int.parse(matched);
       }
 
@@ skipping 369 matching lines @@
    * In accordance with ISO 8601
    * a week starts with Monday, which has the value 1.
    *
    *     DateTime moonLanding = DateTime.parse("1969-07-20 20:18:00");
    *     assert(moonLanding.weekday == 7);
    *     assert(moonLanding.weekday == DateTime.SUNDAY);
    *
    */
   external int get weekday;
 }