Performance warning adjustments

[PenguinKeeper7]

This makes the "Cracking performance lower than expected?" warning more forgiving before displaying. The previous behaviour would trigger if performance dropped at least 10 times over the entire run, checked in 1 second intervals. This means it's almost guaranteed to trigger on longer runs, just by pure chance. This patch makes it so you'd have to fail the kernel time and util checks many times in a short period instead of over the entire run. The counter decreases with every successful check and increases with every failed check instead of only ever increasing.
This patch will also stop checking when Hashcat is [p]aused instead of continuing to check as normal.

Thanks to @roycewilliams finding the pausing issue!