Replace uses of 'std::random_shuffle' with non C++14 deprecated functionality

A couple of VTK-m tests use std::random_shuffle to randomize the order of some input data. Instead we should use something like:

std::vector<int> ids;
std::random_device rng;
std::mt19937 urng(rng());
std::shuffle(ids.begin(), ids.end(), urng);