Merge branch 'selftests-bpf-reduce-tcp_custom_syncookie-verification-complexity'

Eduard Zingerman says:

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selftests/bpf: reduce tcp_custom_syncookie verification complexity

Thread [0] discusses a fix for bpf_loop() handling bug.
That change makes tcp_custom_syncookie test too complex to verify.
The fix discussed in [0] would be sent via 'bpf' tree,
tcp_custom_syncookie test is not in 'bpf' tree yet.
As agreed in [0] I'm sending syncookie test update separately.

[0] https://lore.kernel.org/bpf/20240216150334.31937-1-eddyz87@gmail.com/
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Link: https://lore.kernel.org/r/20240222150300.14909-1-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>