core dumps in test: main

https://travis-ci.org/openquery/mariadb-server/jobs/60083408

main.sp_trans_log 'innodb_plugin'
main.stat_tables_rbr 'innodb_plugin'
main.partition_innodb_stmt 'innodb_plugin'
main-test_sql_discovery.mdl_sync 'innodb_plugin'
main.lock_sync 'innodb_plugin'
main.ctype_utf8 'innodb_plugin'
main.ctype_utf8mb4 'innodb_plugin'
main.mysqldump-max 'innodb_plugin'

core dumps and private uploads in travis-ci.org-openquery-mariadb-server-jobs-60083408#139.25-22357ffedc069180b64744bfa77e0ba4f2596ebc.tar.bz2 (hopefully)