Use IntPSQ instead of OrdPSQ for timers map.

[Saizan]

Using IntPSQ is much faster (20x) on some larger loads, and is recommended by psqueues where possible.

[bolt12]

Great! Could you make the changes for IOSimPOR too?

[Saizan]

@bolt12 sure! Btw, is there something we could use to benchmark the runqueue field? We likely want to change that to HashPSQ.

[bolt12]

@bolt12 sure! Btw, is there something we could use to benchmark the runqueue field? We likely want to change that to HashPSQ.

I guess you can use https://github.com/IntersectMBO/ouroboros-network/blob/main/ouroboros-network/sim-tests-lib/Test/Ouroboros/Network/Testnet.hs#L121

[Saizan]

The tests performance seem unaffected by the changes, probably not enough threads to make it relevant, but should likely help otherwise.

Also I had to add an orphan Hashable (Down a) instance, let me know if you'd prefer it to be moved or if you have other comments about coding style.

[bolt12]

LGTM! Thank you !!