Recognize the deprecated parameters innodb_file_format, innodb_large_prefix

The following parameters were deprecated in MariaDB 10.2.2 and removed in MariaDB 10.3.1:

innodb_file_format
innodb_file_format_check
innodb_file_format_max
innodb_large_prefix
innodb_support_xa
innodb_use_mtflush, innodb_mtflush_threads
innodb_instrument_semaphores
innodb_use_fallocate

The parameters innodb_file_format and innodb_large_prefix were overridden in many configuration files, because the default values of these parameters between MariaDB 5.5 and MariaDB 10.2 did not make any sense.

To allow a more seamless upgrade from MariaDB 10.1 to later versions, let InnoDB recognize the parameters innodb_file_format and innodb_large_prefix and issue deprecation warnings for them if they are specified. A deprecation period of only one major release (one year) is insufficient for these widely used parameters.

This report is motivated by Debian Bug #920608 mariadb-server-10.3: unknown variable 'innodb-large-prefix=on'.