dist/common/scripts/scylla_util.py: make run()/out() functions shorter
dist/common/scripts/scylla_util.py: make run()/out() functions shorter

Refactored these functions to make them simpler.

scylladb/scylla,scylladb/scylla,scylladb/scylla,duarten/scylla,avikivity/scylla,duarten/scylla,avikivity/scylla,scylladb/scylla,duarten/scylla,avikivity/scylla