QUIC: do not send STOP_SENDING after STREAM fin. Previously STOP_SENDING was sent to client upon stream closure if rev->eof and rev->error were not set. This was an indirect indication that no RESET_STREAM or STREAM fin has arrived. But it is indeed possible that rev->eof is not set, but STREAM fin has already been received, just not read out by the application. In this case sending STOP_SENDING does not make sense and can be misleading for some clients.