HPCC-12443 Improve distributor tracing

Improve tracing to distinguish which distributor is tracing,
in activities with multiple distributors.

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
It is unrelated, so fair enough.
But I like '*MORE's in code - they are more prominent and likely to be revisited than a low-priority JIRA, when looking at issues that overlap with code with comments like these.