MDL-59099 dml: MySQL8 supports only the Barracuda file format.

The following InnoDB file format configuration parameters were deprecated
in MySQL 5.7.7 and are now removed:
- innodb_file_format
- innodb_file_format_check
- innodb_file_format_max
- innodb_large_prefix

File format configuration parameters were necessary for creating tables
compatible with earlier versions of InnoDB in MySQL 5.1.
Now that MySQL 5.1 has reached the end of its product lifecycle,
the parameters are no longer required.

The FILE_FORMAT column was removed from the INNODB_SYS_TABLES and
INNODB_SYS_TABLESPACES Information Schema tables.

Ref: https://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-0.html

lib/dml/mysqli_native_moodle_database.php

@@ -307,6 +307,18 @@ public function get_row_format($table = null) {
                       FROM INFORMATION_SCHEMA.TABLES
                      WHERE table_schema = DATABASE() AND table_name = '{$this->prefix}$table'";
         } else {
+            if (($this->get_dbtype() == 'mysqli') &&
+                // Breaking change in MySQL 8.0.0+: antelope file format support has been removed.
+                version_compare($this->get_server_info()['version'], '8.0.0', '>=')) {
+                $dbengine = $this->get_dbengine();
+                $supporteddbengines = array('InnoDB', 'XtraDB');
+                if (in_array($dbengine, $supporteddbengines)) {
+                    $rowformat = 'Barracuda';
+                }
+
+                return $rowformat;
+            }
+
             $sql = "SHOW VARIABLES LIKE 'innodb_file_format'";
         }
         $this->query_start($sql, NULL, SQL_QUERY_AUX);
@@ -384,6 +396,12 @@ public function is_file_per_table_enabled() {
      * @return bool True if on otherwise false.
      */
     public function is_large_prefix_enabled() {
+        if (($this->get_dbtype() == 'mysqli') &&
+            // Breaking change since 8.0.0: there is only one file format and 'innodb_large_prefix' has been removed.
+            version_compare($this->get_server_info()['version'], '8.0.0', '>=')) {
+            return true;
+        }
+
         if ($largeprefix = $this->get_record_sql("SHOW VARIABLES LIKE 'innodb_large_prefix'")) {
             if ($largeprefix->value == 'ON') {
                 return true;