log: Remove unnecessary timing logs for Callbacks bench

Summary:
Logging of Callbacks are no longer needed and records events that are not relevant for performance analysis.
This is a backport of core#23072

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D12245