ci: Use deleteDir() (non Docker workers) to cleanup workspace directory

[big-r81]

Overview

We can use deleteDir() at the end of the native stages. On Windows the cleanup command doesn't work completely, replace it with the provided Jenkins method. Use it at the other native CI workers too.

Checklist

• This is my own work, I did not use AI, LLM's or similar technology
• Code is written and works correctly
• Changes are covered by tests
• Any new configurable parameters are documented in rel/overlay/etc/default.ini
• Documentation changes were made in the src/docs folder
• Documentation changes were backported (separated PR) to affected branches

[nickva]

+1 if ci passes ("if I fits, I sits")