Update test for getprotobyname and getprotobynumber for inconsistant protocol 0

[matt-h]

Depending on the system protocol 0 can be ip or hopopt. On Arch Linux it is hopopt while the former test here assumed it to always be ip

So, this test would fail if run from an Arch Linux system.

Arch gets its protocol list for /etc/protocols from
https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xml
https://sources.archlinux.org/other/packages/iana-etc/protocol-numbers-20260310.xml

I've updated the tests here so it can still pass with ip or hopopt being protocol 0.

[greptile-apps]

Greptile Summary

This PR makes protocol-zero tests independent of whether the host names protocol 0 ip, hopopt, or another valid canonical name.

• Removes protocol-zero assertions from tests with fixed platform-specific output.
• Adds a dynamic name-to-number round-trip test for protocol zero.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains; the new test obtains the host-defined protocol-zero name dynamically and verifies that it resolves back to zero.

Important Files Changed

Filename	Overview
tests/codegen/io/streams.rs	Replaces hard-coded protocol-zero naming expectations with a host-defined round-trip assertion, fully addressing the previous portability finding.

_{Reviews (2): Last reviewed commit: "test: make protocol zero round-trip port..." | Re-trigger Greptile}

[nahime0]

Given that this is a mere test fix, I'm gonna merge as is without further reviews.