QLocale - Fix Mac date format code translation

Mac uses the CLDR format codes which need to be translated into their
Qt equivalent. The existing code mistranslates the year code, is
outdated for a number of new codes introduced in recent versions of
CLDR, and by default accepted any codes it didn't recognize.

This change updates support to the latest version of CLDR, fixes the
treatment of years, and defaults to ignoring any new format codes
added in the future.

Back-ported from qtbase/77dc33dcdbe0eec8ddc9059c4e0ff9dde264c5fa

Task-number: QTBUG-25057

Change-Id: Ide040eca467cfada46fb0e2010db179a76b3096a
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>