HPCC-10052 - Fix NWayInput/NWaySelect

These activities had apparently never worked.
The inputs were not being started or stopped correctly.

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #4872 from jakesmith/hpcc-10052

HPCC-10052 - Fix NWayInput/NWaySelect

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>