Fix Herwig 7.2 dijet JOs JZ1/JZ6 for large output

Description of bug

The bug was discussed in this JIRA ticket, https://its.cern.ch/jira/browse/ATLMCPROD-10870 Many of the jobs are generating log or stdout files too big. I increased the working disk size to 70GB and many jobs still fail.

Changes introduced

Edited JOs for the problematic slices: JZ1 and JZ6 including a suitable line to reduce the number of output lines and therefore the size of the log.generate file (it should be a factor 4 smaller now).

Tests

Tests are done.

Issues resolved

Closes #