Fix usage log timestamp generation
What does this MR do?
Fix usage log timestamp generation
While working on the usage log (!5202 (merged)) and preparing tests for it, timestamp generation was refactored in a way that allows the time to be stubbed during tests.
Unfortunately, it was done in a very wrong and stupid way, that now saves the time of the first usage log entry creation since when runner was started, and then uses that timestamp forever...
This commit fixes this bug and ensures that we have a test coverage for this specific problem.