Fix wrong offset in large logs when some are skipped.

[thesvistun]

Timestamps in large logs written to console have wrong
positive offset when logs are partly skipped. So you never
see the last timestamp in the situation.

Changes made in commit 5a5e7b9 touch Parse From Finish logic
and began the offset.
They were partly reverted.

[basil]

Have you been running this in production, and has it fixed your problem without causing any regressions?

[thesvistun]

Hi, basil.
I have been running this in test instance. The change has fixed my problem. The plagin of v1.17 was used for the purpose.. No regressions were noticed. It is inconvenient to use plugins of custom versions on production, so I'm going to wait for the next release.

[basil]

Hi @thesvistun, please install the incremental build from this PR

https://repo.jenkins-ci.org/incrementals/org/jenkins-ci/plugins/timestamper/1.19-rc755.45f101ddd78a/

on your production server and run it for a week or so. Instructions on how to do so are here:

https://www.jenkins.io/doc/book/managing/plugins/#advanced-installation

Once this change has been verified on a production instance without regressions I will perform a release.

[thesvistun]

Deal.

[thesvistun]

Hi, @basil.
No regression has been noticed for more then requested term.

[basil]

Thanks for the PR!

[basil]

Released in 1.19.

[thesvistun]

Thank you too!