more tests
fix for 2-level ft indexes and boolean search in Aria
update the code to match semantics of `key` - it's not a (char*) pointer to the buffer as in MyISAM.
Two bugs in Aria, related to 2-level fulltext indexes: * REPAIR calculated the key number incorrectly * CHECK copied the key into last_key too early and checking the second-level btree was overwriting it