HPCC-12282 Move roxie query stats to use new mechanism

Prior checkin was not resetting aborted flag, meaning all slave queries would
fail after any one did.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #6583 from richardkchapman/roxie-stats-abort

HPCC-12282 Move roxie query stats to use new mechanism

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>