[ENH] Chronology-j-ConvertTDateTTimeTTimestamp2of2.3.cs ( current version ) ( [er][su][et] [BUG] TimeStamp minusSeconds: incorrect across midnight )

[tomkoenig at mindspring.com]

Subtracting seconds from a TimeStamp appears to give the wrong results
when the new value is for the prior day. An example of the problem:
((TimeStamp readFrom: '1-02-2005 12:34:56 am' readStream) minusSeconds:
34*60+57 )dateAndTime   -->#(1 January 2005 11:25:03 pm)
where it should --> #(1 January 2005 11:59:59 pm)
Examples of clean tests:
((TimeStamp readFrom: '1-02-2005 12:34:56 am' readStream) minusSeconds:
34*60+56 )dateAndTime  correctly shows -->#(2 January 2005 12:00 am)
((TimeStamp readFrom: '1-02-2005 12:34:56 pm' readStream) minusSeconds:
34*60+57 )dateAndTime -->#(2 January 2005 11:59:59

Tested with 3.7a #5623 plus Chronology change sets :
[ENH] Chronology-AnsiCompTests
[ENH] Chronology-c-ANSIDateAndTimeDuration ( current version )
[ENH] Chronology-d-YearMonthWeekRefactoring ( current version )
[ENH] Chronology-e-TemporaryDateTimeTimeSpan ( current version )
[ENH] Chronology-f-ANSICompatibilitySansDateAndTimeDuration.2.cs
[ENH] Chronology-i-ConvertTDateTTimeTTimestamp1of2.2.cs ( current
version )
[ENH] Chronology-j-ConvertTDateTTimeTTimestamp2of2.3.cs ( current
version )
[ENH] Chronology-l-Morphic.2.cs