Errata: chapter 4 - Testing "resume" feature sometimes fails and sometimes works successfully

**Chapter:** 4 
**Description:** Testing resume feature sometimes fails and sometimes works successfully
**Reproduction steps:** Complete chapter 4. Run tests program. 

I have tried adding sleep in case resume doesn't update the /proc/pid/stat file immediately but I am kind of lost on what could be a solution.

Tried this on both Ubuntu 22.04 and Arch Linux 2025.09.01
