add nEventsPerJob to some JOs for ATLMCPROD-8365

Description of bug

For ATLMCPROD-8365

Changes introduced

Add nEvents to various JOs crashing due to a Pythia-8 bug which will be fixed upstream. This nEvents mitigates the symptoms but does not treat the disease.

To quote @mshapiro

OK. I've verified that if I run the standalone main89 example in Pythia8 using the LHE file from Cyril it works in release 8.240 and fails in release 8.244. So the change is definitely on the Pythia8 end and not on our end. I'm going to send the file to Stefan Prestel and ask him to explain what is going on.

Tests

None.

Issues resolved

None.

./cc @zmarshal @ewelina @ppani

@cgutscho @mnegrini - please obsolete/delete the following DSIDs:

500569
500570
500571
500572
500573
500574
500575
500576
500577
500582
500583
500584
500594
500595
500596
500597
500598
500599
500600
500601
500602
500607
500608
500647
500650
500651