selftest: packetdrill: Add test for TFO_SERVER_WO_SOCKOPT1.

TFO_SERVER_WO_SOCKOPT1 is no longer enabled by default, and
each server test requires setsockopt(TCP_FASTOPEN).

Let's add a basic test for TFO_SERVER_WO_SOCKOPT1.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250927213022.1850048-6-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/packetdrill/tcp_fastopen_server_basic-no-setsockopt.pkt

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Basic TFO server test
+//
+// Test TFO_SERVER_WO_SOCKOPT1 without setsockopt(TCP_FASTOPEN)
+
+`./defaults.sh
+ ./set_sysctls.py /proc/sys/net/ipv4/tcp_fastopen=0x402`
+
+    0 socket(..., SOCK_STREAM|SOCK_NONBLOCK, IPPROTO_TCP) = 3
+   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
+   +0 bind(3, ..., ...) = 0
+   +0 listen(3, 1) = 0
+
+   +0 < S 0:10(10) win 32792 <mss 1460,sackOK,nop,nop,FO TFO_COOKIE,nop,nop>
+   +0 > S. 0:0(0) ack 11 <mss 1460,nop,nop,sackOK>
+
+   +0 accept(3, ..., ...) = 4
+   +0 %{ assert (tcpi_options & TCPI_OPT_SYN_DATA) != 0, tcpi_options }%
+
+   +0 read(4, ..., 512) = 10