Gracefully handle cropped DB Stats log dumps

[udi-speedb]

We've seen many cases in which the DB stats section in the log was cropped. This usually occurs when there are many cf-s. In that case, the log entry is sizeable and may be cropped at any point.
The result is that the log parser processes text that is malformed. There have been multiple cases where it has crashed due to that (assertions) and we've had to fix them each time they were discovered.
Being robust in face of such events should be manifested by the parser globally. However, these are common in DB Stats.

The purpose is to review the code, add applicable unit tests, and being able to gracefully discard the applicable text lines from the malformed DB Stats text.