Probtest can't read interleaving time tables

[faeglas]

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