Deal with yet another issue related to "Norwegian (Bokmål)" locale.

It emerges that recent versions of Windows (at least 2016 Standard)
spell this locale name as "Norwegian Bokmål_Norway.1252", defeating
our mapping code that translates "Norwegian (Bokmål)_Norway" to
something that's all-ASCII (cf commits db29620d and aa1d2fc5).
Add another mapping entry to handle this spelling.

Per bug #16068 from Robert Ford.  Like the previous patches,
back-patch to all supported branches.

Discussion: https://postgr.es/m/16068-4cb6eeaa7eb46d93@postgresql.org