Update the gdatetime Test Program for Windows
Update the gdatetime Test Program for Windows

Update the gdatetime test program to make use of the updates that was
done in gtimezone.c in the previous commit, so that we don't have to
worry what language version of Windows the tests are being run in, but
instead be assured that we produce and check for the English-language
time zone name strings.

Also, instead of testing for "Pacific Standard Time" in
test_GDAteTime_printf(), use GetDynamicTimeZoneInformation() to get the
actual time zone string (where the system running the test program is)
we want to check for, because on Windows the actual result will be
dependent on which timezone the system running the test program is in.

https://bugzilla.gnome.org/show_bug.cgi?id=719344

endlessm/glib,endlessm/glib,endlessm/glib,endlessm/glib,endlessm/glib