"Cron run completed" not logged

Problem/Motivation

At some point I'm pretty sure that this core message appeared in db log. It's valuable information to understand if cron is working correctly or not. We use it for monitoring if cron is ok.

Steps to reproduce

1. Run cron in vanilla Drupal and see that the message "Cron run completed" appears in logs after running cron.
2. Install Ultimate Cron, run cron and check that the message does not appear

Proposed resolution

Add this log or allow core message to come through upon completion.

Remaining tasks

User interface changes

API changes

Data model changes