HPCC-8688 Generate rows with constant sets as compile time constants

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #3919 from ghalliday/issue8688

HPCC-8688 Generate rows with constant sets as compile time constants

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>