[FIX] base: Arabic generic World locale is ar_001
[FIX] base: Arabic generic World locale is ar_001

Before this commit, the "unitag" notation "xx_AA" was used for arabic generic locale
Since it is not an official Unicode CLDR notation, some other modules
may, and did crash (babel)

Instead, we prefer to use Unicode CLDR compliance
i.e. World regions should be "_001"

http://www.unicode.org/reports/tr35/#unicode_region_subtag
http://www.unicode.org/reports/tr35/#unicode_region_subtag_validity
BCP47: https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry

This commit should invalidate the commit made by #32344
which was a hack for stable versions

It should also be taken into account in migration scripts

closes odoo/odoo#32393

Signed-off-by: Olivier Dony (odo) <d670d44c3ca8bd4cd53a3b09f8bf8fc35e4843cc@openerp.com>
ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo