module HMRClient is not callable

React Native Debugger app version: 0.8.2
React Native version: 0.57
Platform: iOS
Is real device of platform: No
Operating System: macOS High Sierra

Getting error `module HMRClient is not callable` only in latest release of 0.8.2 debugger.

When RN Debugger connects and runs fine after first connect, but after first hot reload, client throws error module HMRClient is not callable.


Note, older versions of RN debugger work and chrome debugger works fine as well.

Note about this environment, it's got it's own babelrc that follows the latest react native guidelines:

```
{
"presets": ["module:metro-react-native-babel-preset"]
}
```

Riproduci il malfunzionamento nell’app React Native Debugger 0.8.2 con React Native 0.57 su iOS, concentrandoti sul primo hot reload dopo una connessione riuscita. Confronta questo comportamento con una versione precedente del debugger e con il debugging in Chrome; il lavoro è completato quando l’hot reload termina senza l’errore “module HMRClient is not callable”.

Scritto dal modello di indicizzazione a partire dal testo della issue.