Initial fixes to Hebrew calendar resulting from QA review.

1. Remove experimental code that was confusing things (and should never have been committed in the first place as isn't completed yet).
2. Fix setDate() issues from calling base class in error
3. Fix problem with not returning month name for month 13
4. More unit tests including round tripping
5. Restrict valid date range to AH 5344 to 8119 (AD 1583 to 4359) as testing shows this is the range the current formula implementations actually work in

These fixes use the existing formulas, better formulas are available and will
be implemented later.

(Note round-trip tests show a bug in QDate with leap days in years < 1!)

BUG: 220990

Fixes implemented for 4.4 only