HPCC-9515 Add support to move rows from one heaplet to another.

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #4533 from ghalliday/issue9515

HPCC-9515 Add support to move rows from one heaplet to another.

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>