Unbreak net tile parallelism

[ripatel-fd]

Firedancer main as of abbe48de18469415df8bfd49b4a0f3eda561233b only supports running with one net tile.

There are two bugs preventing it from scaling:

• The /proc/pid/fd handover mechanism for BPF maps is broken (needs to be deleted)
• quic<=>net topology code crashes