Without this change, for Japan, Wine returns "Korea Standard Time",
not "Tokyo Standard Time" as seen in Bug 42719.

Actually, this is a regression by d666143f.
The new code relies on offsets from UTC and DST change timings.  However,
Northeast Asia regions don't use daylight saving time.  Thus, Wine can't
distinguish between these regions.
Signed-off-by: Akihiro Sagawa <sagawa.aki@gmail.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>