Finalize log stream before exiting process

Reviewed By: antonk52

Differential Revision: D51229230

fbshipit-source-id: 0e7f657a170eb8602ade9abf1db1976c5b51dc3f

desktop/flipper-server-core/src/FlipperServerImpl.tsx

@@ -583,6 +583,7 @@ export class FlipperServerImpl implements FlipperServer {
       return uploadRes;
     },
     shutdown: async () => {
+      // Do not use processExit helper. We want to server immediatelly quit when this call is triggerred
       process.exit(0);
     },
     'is-logged-in': async () => {