Neptune Hash Implementation

[cool-develope]

What does this PR do?

• Implement the more optimized version in the goldenhash
• Add the benchmark of 12 elements to compare

Benchmark Results

cpu: Intel(R) Core(TM) i5-9400 CPU @ 2.90GHz BenchmarkPoseidonHash-6 21825 53427 ns/op BenchmarkNeptuneHash-6 61786 18725 ns/op BenchmarkPoseidonHash12Inputs-6 10000 120578 ns/op

References

• https://github.com/hermeznetwork/zkevm-commonjs/blob/main/src/poseidon_opt.js
• https://github.com/hermeznetwork/zkevm-commonjs/blob/main/src/poseidon_constants_opt.js

[cool-develope]

I general looks good. But do you need two implementations of the same hash function: original one and the optimized one?

OK, I will remove the original one