Check fork-choice rule implementation when forked block is outside of window

[sbazerque]

I think there may be a mistake on the filtering of gossip or in the rule itself, saw a failing example in a small testnet.

[jio-gl]

Ok, maybe is a border case in the limit of the finality window? We can later change the name from Finality Depth to Finality Window, sounds like the later name stuck up more.

[sbazerque]

The problem turned out to be in HHS' networking code - tested fork choice outside the window and everything seems to work fine.

[jio-gl]

Perfect @sbazerque.

[jio-gl]

Great news.