### Overview
Some Executors, currently a subset of the local Executors, run in a single threaded fashion and have certain limitations and requirements, many of which are hardcoded. To add a new single threaded Executor would require changes to core Airflow code.
Note: This coupling often shows up with SQLite compatibility checks since it does not support multiple connections.
### Examples
- **2a**) SQLite check done in configuration.py: https://github.com/apache/airflow/blob/26f94c5370587f73ebd935cecf208c6a36bdf9b6/airflow/configuration.py#L412-L419
- **2b**) When running in standalone mode SQLite compatibility is checked: https://github.com/apache/airflow/blob/26f94c5370587f73ebd935cecf208c6a36bdf9b6/airflow/cli/commands/standalone_command.py#L160-L165
- **2c**) Sensors in `poke` mode can block execution of DAGs when running with single process Executors, currently hardcoded to DebugExecutor (although should also include SequentialExecutor): https://github.com/apache/airflow/blob/27e2101f6ee5567b2843cbccf1dca0b0e7c96186/airflow/sensors/base.py#L243
### Proposal
A static method or attribute on the Executor class which can be checked by core code.

There is a precedent already set with the `supports_ad_hoc_ti_run` attribute, see:
https://github.com/apache/airflow/blob/fb741fd87254e235f99d7d67e558dafad601f253/airflow/executors/kubernetes_executor.py#L435 https://github.com/apache/airflow/blob/26f94c5370587f73ebd935cecf208c6a36bdf9b6/airflow/www/views.py#L1735-L1737
return time.monotonic() - start_monotonic
        try_number = 1
        log_dag_id = self.dag.dag_id if self.has_dag() else ""
        xcom_value = None
        while True:
            poke_return = self.poke(context)
            if poke_return:
                if isinstance(poke_return, PokeReturnValue):
                    xcom_value = poke_return.xcom_value
                break
            if run_duration() > self.timeout:
                
                message = (
                    f"Sensor has timed out; run duration of {run_duration()} seconds exceeds "
                    f"the specified timeout of {self.timeout}."
                )
                if self.soft_fail:
                    raise AirflowSkipException(message)
                else:
                    raise AirflowSensorTimeout(message)
            if self.reschedule:
                next_poke_interval = self._get_next_poke_interval(started_at, run_duration, try_number)
                reschedule_date = timezone.utcnow() + timedelta(seconds=next_poke_interval)
                if _is_metadatabase_mysql() and reschedule_date > _MYSQL_TIMESTAMP_MAX:
                    raise AirflowSensorTimeout(
                        f"Cannot reschedule DAG {log_dag_id} to {reschedule_date.isoformat()} "