message: Be able to lookup driver by engine alias
diff: @@ -147,6 +147,15 @@ def get_available_engine_specs() -> Dict[Type[BaseEngineSpec], Set[str]]:
  available_engines = {}
  for engine_spec in load_engine_specs():
  - available_engines[engine_spec] = drivers[engine_spec.engine]
  + driver = drivers[engine_spec.engine]
  +
  + # lookup driver by engine aliases.
  + if not driver and engine_spec.engine_aliases:
  + for alias in engine_spec.engine_aliases:
  + driver = drivers[alias]
  + if driver:
  + break
  +
  + available_engines[engine_spec] = driver
  return available_engines
  