Patch #8

To repeat:
./mtr --charset-for-testdb=utf8mb4 --defaults-file=include/utf8mb4_my.cnf

group_min_max_innodb
heap
heap_btree
heap_hash
join_outer
join_outer_bka
join_outer_bka_nixbnl
join_outer_innodb
sp_notembedded

Change-Id: I7f1eb96061a1dfba7bb91afcafa47326c9d079e7