Utils performance for Nants > 2,147,483,648

[mkolopanis]

In the largest antennas configuration there is a performance degradation compared to the other utils functions.

This is most likely from the python interactions in the large Nants utility functions.

I've tried messing with the cython compiler directives like cdivision but it does not seem to fix this issue.

I first noticed this when toying with writing the utilites in rust and noticed the factor of ~10 slow down

compared to the 2048 implementation (and 256)

[mkolopanis]

I would have expected switching to cdivision, and casting 2147483648 to a numpy.uint64_t to resolve this issue. It helps but not fully resolved.