[Intl] Add FallbackTrait for data generation #31432
This is the last architectural change for the Intl data compilation. Promised.
It fixes de-duplicating a locale from its fallback locale. The problem is it uses a while-loop, comparing the locale to each fallback locale.
We have an edge case where a locale (ur_IN) override its fallback locale (ur), setting/restoring the value back to the root locale. This happens for the GMT format in the timezone bundle i know of ... in this case the
The current approach is a while-loop comparing each fallback locale (ur, root) to the current locale (ur_IN). Eventually comparing
The new approach uses recursion so we only compare