Improve stability of the benchmark

[darnuria]

Some benches were not totally stable on my computer (it's really hot these days, maybe I hit the temp freq switch of my cpu in the benches)

But on some case maybe black boxing and increasing the measurement (now 100 by default) is a start:

doc of criterion black_box: https://docs.rs/criterion/latest/criterion/fn.black_box.html

[sunng87]

Our benchmark is highly CPU-intensive, so the condition of your system and CPU throttle matters. Could you please verify if block_box really help?

[darnuria]

Hi, thanks for the reply, it passed under the radar, may have some time to do some tests this week with/without black-box on personnal and work computers.

[darnuria]

Sorry will close for inactivity didn't found time to work on it. And since I didn't provided "strong" fact better just close it. :)