Better solution for PGO lab

[0legmak]

Currently, this lab requires manual generation of profile data. There is a better way: integrate profile collection into the build process. This way profile data is always up to date and does not require changes when upgrading a compiler.

Example implementation: https://github.com/dendibakh/perf-ninja/blob/e097f27127e736412468bb39173c93df9dfeddd2/labs/misc/pgo/CMakeLists.txt

CI run: https://github.com/dendibakh/perf-ninja/actions/runs/14020883047/job/39252687197

Some problems I have not been able to solve yet:

• It uses a relatively new CMake feature LIST:REMOVE_ITEM, which is not available on every CI machine.
• Path to llvm-profdata is hard coded.

[0legmak]

Resolved issues in newer version: https://github.com/dendibakh/perf-ninja/blob/6738ccd9e6afc4c23424fee82fa44c25cd594e69/labs/misc/pgo/CMakeLists.txt

Commit with CI checks: 6738ccd