[Enhancement] BPF unit test

[jschwinger233]

Improvement Suggestion

Let's test the important route() function in bpf.

Potential Benefits

If we are changing something regarding route(), e.g. using bpf_tailcall instead of bpf2bpf to lift limit of verifier complexity, it's better we have this core function covered.

[dae-prow[bot]]

Thanks for opening this issue!

[jschwinger233]

Just self-assigned this. Really wanna cover the intimidating route() bpf function in CI test before we add more flavors into it.