HPCC-12201 Disable implicit LOOKUP creation for joins in hthor/roxie

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #31 from ghalliday/issue12201

HPCC-12201 Disable implicit LOOKUP creation for joins in hthor/roxie

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>