HPCC-11341 - Add tracing for block splitters

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #5808 from jakesmith/hpcc-11341

HPCC-11341 - Add tracing for block splitters

Reviewed-By: Gavin Halliday <gavin.halliday@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>