KLists kpoint sorting inconsistent across compiler in mixed precision

The sorting of kpoints into shells is different for clang 19 and gcc 14 and seemingly other clang and gcc's at least debug.
This makes testing the Structure Factor Estimator with a realistic kgrid for a realistic unit cell a mess.
It also is indicative that the KContainer unit testing is completely insufficient.

I also don't see any reason that or kpoint sorting shouldn't be 100% the same for all platforms and precision.

Related to #2445, #2137, #2105. It can't do diamond, the shell sorting algorithm should never have made it out of unit testing.

Currently its invisible but I have two different unit tests my branch which clearly show it. Sorting is different between full and mixed precision and between gcc and clang mixed sorting.