Merge branch 'selftests-net-packetdrill-netns-and-two-imports'

Willem de Bruijn says:

====================
selftests/net: packetdrill: netns and two imports

From: Willem de Bruijn <willemb@google.com>

1/3: run in nets, as discussed, and add missing CONFIGs
2/3: import tcp/zerocopy
3/3: import tcp/slow_start
====================

Link: https://patch.msgid.link/20240912005317.1253001-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>