Decrease the default number of events in TrigP1Test ART-local tests
Run TrigP1Test ART-local tests on 80 events instead of 100 to save some time. With the Trigger Menu growing rapidly in the past few weeks towards the Run-3 menu sign-off, the tests started to take a bit too much time and cause problems. It's a pity to resort to this solution, but there doesn't seem to be any better option for improving performance in a short term.
Fixes ATR-23767 albeit in an unsatisfactory way slightly decreasing the testing coverage.
cc @astruebi, @palacino, @dzanzi, @khoo, @markowen, @okumura, @vmartin