MDL-75283 core: Fetch proper column mapping for sort

Calling \core_user\fields::get_sql() incerements a static uniqueid
variable. This should be called only once and not make a separate call
for the sort mapping data as it doing so will result to an incorrect
table alias for the sort mapping data.

lib/datalib.php

@@ -529,23 +529,19 @@ function get_users_listing($sort='lastaccess', $dir='ASC', $page=0, $recordsperp
         $userfields->with_identity($extracontext, true);
     }
 
+    $userfields->excluding('id');
+    $userfields->including('username', 'email', 'city', 'country', 'lastaccess', 'confirmed', 'mnethostid', 'suspended');
+    ['selects' => $selects, 'joins' => $joins, 'params' => $joinparams, 'mappings' => $mappings] =
+            (array)$userfields->get_sql('u', true);
+
     if ($sort) {
-        $possiblesortfields = \core_user\fields::for_name();
-        if ($extracontext) {
-            $possiblesortfields->with_identity($extracontext);
-        }
-        $orderbymap = $possiblesortfields->including('id', 'city', 'country', 'lastaccess', 'confirmed', 'mnethostid', 'suspended');
-        $orderbymap = $orderbymap->get_sql('u', true)->mappings;
+        $orderbymap = $mappings;
         $orderbymap['default'] = 'lastaccess';
         $sort = get_safe_orderby($orderbymap, $sort, $dir);
     }
 
-    $userfields->excluding('id', 'username', 'email', 'city', 'country', 'lastaccess', 'confirmed', 'mnethostid');
-    ['selects' => $selects, 'joins' => $joins, 'params' => $joinparams] =
-            (array)$userfields->get_sql('u', true);
-
     // warning: will return UNCONFIRMED USERS
-    return $DB->get_records_sql("SELECT u.id, username, email, city, country, lastaccess, confirmed, mnethostid, suspended $selects
+    return $DB->get_records_sql("SELECT u.id $selects
                                    FROM {user} u
                                         $joins
                                   WHERE $select