HPCC-12215 Roxie record counts missing from child queries

Create the stats gatherer sooner.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-12215 Roxie record counts missing from child queries

Update the wu stats in the activirty destructor rather than the reset - this
will be much more efficient for child queries.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #6513 from richardkchapman/roxie-child-stats2

HPCC-12215 Roxie record counts missing from child queries

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>