remove unnecessary conditions in Matrix::compute_rank

[x100111010]

by @Slixe

In fn compute_rank(&self) remove the if condition previously used to remove the bounds check.
According to the issue linked (rust-lang/rust#90794) it has been fixed since 1.72.

@0xA001113 We should check if we can make more improvements like this.

[0xA001113]

I understand why Kaspa didn't want to merge it for now as it is risky consensus critical change. I did already some basic smoke testing:

1. Running a devnet on 1 node.
2. Running a testnet on 3 nodes with the changes and mine against the nodes, sync it afterwards from a node without the changes.
3. Running a testnet on 2 of 3 nodes with the changes, 1 of 3 nodes without the changes and mine against the nodes.
4. Running a testnet on 1 of 3 nodes with the changes, 2 of 3 nodes without the changes and mine against the nodes.
5. Running a mainnet node with the changes, and N nodes without the changes and mine against the nodes.

Moreover, I've tested this patch for quite some time now in our mainnet and testnet and so far all looks good. However I can measure the performance improvement only during benchmark and no real enhancement in production use with 1bps networks. Haven't tested 10bps yet.

I will merge it for now as I like to removal of unsafe code. @Slixe: Many thanks!

[Slixe]

let me do better then..