only when the specified language is Greek; loses data from the string (won't roundtrip with lowercasing)
Currently, Blink (Chromium and Opera's rendering engine) uses ICU's transliterator for Greek uppercasing. It'd be nice not to special-case Greek.
See also http://unicode.org/cldr/trac/ticket/7905 about doing even more than what's talked about here.
Duplicate of ICU 58 ticket #5456.