Workaround for SR-16097 to avoid hitting SR-16095: VSCode will send shutdown requests without a 'params' key. On macOS getting the superDecoder for a non-existent container returns an empty decoder, on Linux it throws `DecodingError.keyNotFound`, causing a crash.
Perform a targeted fix: If we don't have 'params' and the request is a ShutdownRequest, manually create a `ShutdownRequest` without any parameters.
rdar://91288093
* Replaces two logs since those don't result in response messages anymore
* Adds a func for sending messages synchronously, to get the two messages out before fatalError
