HPCC-8833 Assume keyed join is sorted unless UNORDERED

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
HPCC-8833 Remove unused macro definition

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #6643 from ghalliday/issue8833

HPCC-8833 Assume keyed join is sorted unless UNORDERED

Reviewed-By: Jake Smith <jake.smith@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>