HPCC-8833 Assume keyed join is sorted unless UNORDERED

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
No - because now it will always be sorted, unless they have explicitly added ,UNORDERED to the JOIN.  Previously I don't think that flag was ever set for hthor/thor, but the option always defaulted to true.