Fix integer overflows in Elkan's k-means. #15057
Unfortunately I don't understand what kind of test that should be.
I could add testing for large arrays in k-means, but that test would consume quite large amount of memory (my estimation is around 16GB). Not many computers are capable of performing such a test. I wonder if it is reasonable to add tests that cannot be performed on the most computers.
It would be quite helpful if guide me in the right direction.