Add update_cdf benchmark.
test update_cdf_bench_c ... bench: 305,013 ns/iter (+/- 29,687) test update_cdf_bench_native ... bench: 322,958 ns/iter (+/- 19,123)
test update_cdf_bench_c ... bench: 305,013 ns/iter (+/- 29,687) test update_cdf_bench_native ... bench: 322,958 ns/iter (+/- 19,123)