[REV] Revert "[IMP] base: select countries & state based on exact code, (useful for import and fast many2one)"

This reverts commit 09a22e3bef, which was
attempting to fix a use case that was actually working.
It also created a duplicate `name_search()` method for res.country, in
addition to the one aliased to `location_name_search()`

It is indeed supported to import countries and states, using the
country code or state code as the imported value. These will be matched
uniquely thanks to the special `name_search()` performed for import,
forcing the `operator`.
And this is done while still allowing proper auto-completing for normal
UI case, where the "exact code match" will only promote an extra result
at the top of the suggested matches, rather than limit the results to a
single match.

The confusion apparently stemmed from the test case using "UK" as the
country code. UK is not a valid ISO country code, so it would never
match as expected.

odoo/addons/base/models/res_country.py

@@ -92,16 +92,6 @@ class Country(models.Model):
         self.ensure_one()
         return re.findall(r'\((.+?)\)', self.address_format)
 
-    @api.model
-    def name_search(self, name='', args=None, operator='ilike', limit=100):
-        if args is None:
-            args = []
-        records = self.search([('code', '=', name)] + args, limit=limit)
-        if not records:
-            search_domain = [('name', operator, name)]
-            records = self.search(search_domain + args, limit=limit)
-        return [(record.id, record.display_name) for record in records]
-
 
 class CountryGroup(models.Model):
     _description = "Country Group"
@@ -132,10 +122,10 @@ class CountryState(models.Model):
             args = []
         if self.env.context.get('country_id'):
             args = args + [('country_id', '=', self.env.context.get('country_id'))]
-        records = self.search([('code', '=', name)] + args, limit=limit)
-        if not records:
-            search_domain = [('name', operator, name)]
-            records = self.search(search_domain + args, limit=limit)
+        firsts_records = self.search([('code', '=ilike', name)] + args, limit=limit)
+        search_domain = [('name', operator, name)]
+        search_domain.append(('id', 'not in', firsts_records.ids))
+        records = firsts_records + self.search(search_domain + args, limit=limit)
         return [(record.id, record.display_name) for record in records]