The relevant MS system calls (say they) don't support date formatting
for years < 1601 (but apparently do in fact) and the year field of the
data structure is unsigned, so can't support years < 0. As a result,
the windows back-end for QSystemLocale failed for negative years.
So replace year < 1601 with a place-holder and substitute after
formatting.
Added new tests (based loosely on one in qtdeclarative that failed) to
verify that this actually works. These reveal that macOS also fails to
handle negative years; marked as expected failure there pending a fix.
Change-Id: I9b63cefd5f0b77a39cf1238549412de3e26ca1bd
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
8926eb86c6