Merge branch 'selftests-bpf-migrate-test_xdp_redirect_multi-sh-to-test_progs'

Bastien Curutchet says:

====================
This patch series continues the work to migrate the *.sh tests into
prog_tests framework.

test_xdp_redirect_multi.sh tests the XDP redirections done through
bpf_redirect_map().

This is already partly covered by test_xdp_veth.c that already tests
map redirections at XDP level. What isn't covered yet by test_xdp_veth is
the use of the broadcast flags (BPF_F_BROADCAST or BPF_F_EXCLUDE_INGRESS)
and XDP egress programs.

Hence, this patch series add test cases to test_xdp_veth.c to get rid of
the test_xdp_redirect_multi.sh:
 - PATCH 1 & 2 Rework test_xdp_veth.c to avoid using the root namespace
 - PATCH 3 and 4 cover the broadcast flags
 - PATCH 5 covers the XDP egress programs

NOTE: While working on this iteration I ran into a memory leak in
net/core/rtnetlink.c that leads to oom-kill when running ./test_progs in
a loop. This leak has been fixed by commit 1438f5d07b9a ("rtnetlink:
fix netns leak with rtnl_setlink()") in the net tree.
====================

Link: https://patch.msgid.link/20250212-redirect-multi-v5-0-fd0d39fca6e6@bootlin.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>