fix(tester.py): move failure logic based on events to one place
fix(tester.py): move failure logic based on events to one place

since we changed the failure logic to include both critical and error events
the `TestResultEvent` doesn't includ this logic,
this change makes sure this check happens before creating `TestResultEvent`

Ref: [trello item](https://trello.com/c/rqZN32Qu)

scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-longevity-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests