With the TRUNCATE by rename, create, drop (MDEV-13564),
old tables with invalid ROW_FORMAT attribute could not be
truncated. Introduce a sloppy mode for allowing the TRUNCATE.

create_table_info_t::prepare_create_table(): Add the parameter
strict=true.

ha_innobase::create(): Pass strict=false if trx!=NULL
(the create is part of TRUNCATE).