Related to https://github.com/apache/airflow/issues/9655

It would be nice to add a message when you get this error with some info, like 'This probably is because a lack of RAM' or something like that. 

I have found the code where the -9 is assigned but have no idea how to add a logging message. 

        self.process = None

        if self._rc is None:
            # Something else reaped it before we had a chance, so let's just "guess" at an error code.
            self._rc = -9
airflow/task/task_runner/standard_task_runner.py
pid = os.fork()
        if pid:
            self.log.info("Started process %d to run task", pid)
            return psutil.Process(pid)
        else:
            import signal
            from airflow import settings
            from airflow.cli.cli_parser import get_parser
            from airflow.sentry import Sentry
            signal.signal(signal.SIGINT, signal.SIG_DFL)
            signal.signal(signal.SIGTERM, signal.SIG_DFL)
            
            os.setpgid(0, 0)
            
            
            
            settings.engine.pool.dispose()
            settings.engine.dispose()
            parser = get_parser()
            
            args = parser.parse_args(self._command[1:])
            self.log.info('Running: %s', self._command)
            self.log.info('Job %s: Subtask %s', self._task_instance.job_id, self._task_instance.task_id)
            proc_title = "airflow task runner: {0.dag_id} {0.task_id} {0.execution_date}"
            if hasattr(args, "job_id"):
                proc_title += " {0.job_id}"
            setproctitle(proc_title.format(args))
            try:
                args.func(args, dag=self.dag)
                return_code = 0