Probtest can't read interleaving time tables

LOG files can contain multiple timing tables. There is no guarantee on the order due to asynchronous output of ICON. In the rare case one table is printed in the middle of the other, the code crashes.
Examples:
- https://bb-prod8.dkrz.de/#/builders/87/builds/800/steps/4/logs/checksuite_icon-dev_check_mch_icon-ch2
- https://bb-prod8.dkrz.de/#/builders/87/builds/631/steps/4/logs/checksuite_icon-dev_check_mch_icon-ch2

Start by reproducing the crash with the two linked build logs and trace the log-reading path that handles timing tables. Done means probtest can read logs with interleaved timing tables without crashing, while continuing to process the tables.

Written by the indexing model from the issue text.