New warning: unused variable `left_o`[-Wunused-variable] in `Python/generated_cases.c.h:186`

# Bug report

See output in https://github.com/python/cpython/pull/125455
<img width="992" alt="Снимок экрана 2024-10-14 в 19 37 26" src="https://github.com/user-attachments/assets/de742b55-c06f-418a-8ebf-deea82f6123e">



### Linked PRs
* gh-125471