IGD+ computation in jMetalPy much slower than moocore

[MLopez-Ibanez]

I tried to benchmark the IGD+ code in jMetalPy against the same function moocore but jMetalPy seems between 100-1000 times slower. You can see my benchmarking code here: https://github.com/multi-objective/moocore/blob/main/python/benchmarks/bench_igdplus.py

Note that moocore also provides AHD: https://multi-objective.github.io/moocore/python/reference/functions.metrics.html#inverted-generational-distance-igd-and-igd-and-averaged-hausdorff-distance