keep both versions of china/taiwan localization icons (bug 1041520)

This fixes the immediate problem, but does highlight that we localize china and taiwan to cn / tw in some places and zh-cn / zh-tw in other places. I don't know how big a deal that is.
wait, I forgot. `tw` isn't a locale. it's a region. so why are we adding `zh-cn` and `zh-tw` (which are locales) as regions? shouldn't we just have two regions, China (`cn`) and Taiwan (`tw`)?