The query might still work depending on where these chars are placed,
but it seems weird to only remove *some* of the valid chars here.
See https://dev.mysql.com/doc/refman/5.6/en/fulltext-boolean.html
Note that the query runs both the actual boolean query with chars,
and then a separate relevance search without them.
MyISAM used to be the only one to support it, now InnoDB has caught up.
Unless an engine is set specifically in create_table_options,
this will auto-convert existing MyISAM tables to InnoDb.
Fixes#9242
