Some CLDR languages.json / territories.json files contain localizations
for some lanuages/territories that are otherwise not present in the CLDR
database. We already don't generate anything in UnicodeLocale.cpp for
these anomalies, but this will stop us from even storing that data in
the generator's memory.
This doesn't affect the output of the generator, but will have an effect
after an upcoming commit to unique-ify all of the strings in the CLDR.
