[ENH] Chronology-i-ConvertTDateTTimeTTimestamp1of2.2.cs ( current version ) ( [su][sm][et] [BUG] Date>>Previous: Wrong when receiver and argument are same day of week )

[tomkoenig at mindspring.com]

When the receiver and operand are the same day of the week,
Date>>Previous: appears to return the receiver rather than a date 7 days
earlier.  For example:
(aDate := Date readFrom: '01-23-2004' readStream)  previous: 'Friday' 
-->23 January 2004
When the previous day of the week differs, the results are ok:
(aDate := Date readFrom: '01-23-2004' readStream)  previous: 'Thursday' 
-->22 January 2004

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