use-of-uninitialized-value in quic_tserver_test

Fixes openssl#26277

Reviewed-by: Saša Nedvědický <[email protected]>
Reviewed-by: Tomas Mraz <[email protected]>
(Merged from openssl#26269)

Author: bernd-edlinger

ssl/quic/quic_demux.c

@@ -442,6 +442,7 @@ int ossl_quic_demux_inject(QUIC_DEMUX *demux,
 
     /* Move from free list to pending list. */
     ossl_list_urxe_remove(&demux->urx_free, urxe);
+    urxe->datagram_id = demux->next_datagram_id++;
     ossl_list_urxe_insert_tail(&demux->urx_pending, urxe);
     urxe->demux_state = URXE_DEMUX_STATE_PENDING;