Graceful shutdown on server group doesn't take into account timeout

The timeout for graceful shutdown in case of domain server groups isn't respected.

Steps to reproduce

1. start server in domain (domain.sh)
2. Deploy application which allows creating long running requests (you can use the one provided in attachment)
3. Create request to server-one (in main server group), which shall take longer time then graceful shutdown for example 50s (curl -v http://127.0.0.1:8080/long-running-servlet/HeavyProcessing?duration=50000)
4. In the mean time call graceful shutdown on main server group (/server-group=main-server-group:stop-servers(timeout=5))

The request should be terminated by server after 5s, still it is fully processed with 200 status code.