### Body

Add unit test for changes in https://github.com/apache/airflow/pull/17305

### Committer

- [X] I acknowledge that I am a maintainer/committer of the Apache Airflow project.
airflow/jobs/backfill_job.py
self.log.error("Task instance %s failed", ti)
                ti_status.failed.add(reduced_key)
                ti_status.running.pop(reduced_key)
                continue
            
            if ti.state == State.UP_FOR_RETRY:
                self.log.warning("Task instance %s is up for retry", ti)
                ti_status.running.pop(reduced_key)
                ti_status.to_run[ti.key] = ti
            
            elif ti.state == State.UP_FOR_RESCHEDULE:
                self.log.warning("Task instance %s is up for reschedule", ti)
                ti_status.running.pop(ti.key)
                ti_status.to_run[ti.key] = ti
            
            
            
            
            
            elif ti.state == State.NONE:
                self.log.warning(
                    "FIXME: task instance %s state was set to none externally or "
                    "reaching concurrency limits. Re-adding task to queue.",
                    ti,
                )
                tis_to_be_scheduled.append(ti)
                ti_status.running.pop(reduced_key)
                ti_status.to_run[ti.key] = ti
        
        if tis_to_be_scheduled: