Port benches to stable

[rukai]

They currently rely on unstable features.
I might have a go at this, do you have a preference of https://github.com/nvzqz/divan or https://github.com/bheisler/criterion.rs

[aembke]

Great idea. I took a stab at porting over the old RESP2 decoding benchmarks, but ran into some friction with the new interface. I need to switch back to some other work in fred, but feel free to have a go at the new interface. I'm sure there are more elegant ways to test the different parameters in there.