1129817 - prepend process id and thread id if line is split

By including a unique identifier, it is possible to separate logs that are generated at the same time.

 [Bugzilla-1129817](https://bugzilla.redhat.com/show_bug.cgi?id=1129817)
Hmm, I wonder if this one will cause problems too. Do we need to adjust relative_ending_index again here?