message: [cluster-test] Return error on experiment failure instead of panic
  This diff is almost no-op - returning error instead of panicing and also removing bunch of commented code(mistakenly pushed in 3a18ec)
  Closes:
  Approved by: ankushagarwal
diff: @@ -604,9 +604,7 @@ impl ClusterTestRunner {
  bail!("Experiment deadline reached");
  }
  result = run_future => {
  - result
  - .expect("Failed to run experiment");
  - return Ok(());
  + return result.map_err(|e|format_err!("Failed to run experiment: {}", e));
  }
  delay = delay_for(HEALTH_POLL_INTERVAL).fuse() => {
  let events = logs.recv_all();
  @@ -622,39 +620,6 @@ impl ClusterTestRunner {
  }
  })?;
  }
  - // let mut experiment_handle = self
  - // .runtime
  - // .spawn(async move { experiment.run(&mut context).await });
  - //
  - // // We expect experiments completes and cluster go into healthy state within timeout
  - // let experiment_deadline = Instant::now() + deadline;
  - // let mut task_context = task::Context::from_waker(noop_waker_ref());
  - // loop {
  - // if Instant::now() > experiment_deadline {
  - // bail!("Experiment did not complete in time");
  - // }
  - // let deadline = Instant::now() + HEALTH_POLL_INTERVAL;
  - // // Receive all events that arrived to aws log tail within next 1 second
  - // // This assumes so far that event propagation time is << 1s, this need to be refined
  - // // in future to account for actual event propagation delay
  - // let events = self.logs.recv_all_until_deadline(deadline);
  - // if let Err(s) = self.health_check_runner.run(
  - // &events,
  - // &affected_validators,
  - // PrintFailures::UnexpectedOnly,
  - // ) {
  - // bail!("Validators which were not under experiment failed : {}", s);
  - // }
  - // match experiment_handle.poll_unpin(&mut task_context) {
  - // Poll::Ready(result) => {
  - // result
  - // .expect("Failed to poll join handle")
  - // .expect("Failed to run experiment");
  - // break;
  - // }
  - // Poll::Pending => {}
  - // }
  - // }
  info!(
  "{}Experiment finished, waiting until all affected validators recover{}",
  