[llvm] [GitHub][CI] Run clang-format natively in ci-ubuntu container (PR #161073)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

> I've checked ~10 different workflow runs ([runs.txt](https://github.com/user-attachments/files/22585137/runs.txt)) and on average it currently takes ~7sec to complete "Setup Python env + Install python dependencies" steps. In my test run, it took 6sec to "Create venv + install dependencies" so it could be even a speedup (or a very small regression)

Ack. Even if it took a bit of time, I think this should be a net positive.

> Apart from it, I observed that setup-python works poorly inside docker environment and in the past I https://github.com/llvm/llvm-project/pull/154829#discussion_r2299002613 to set up custom python and caching for clang-tidy job.

Yeah, especially in a minimal environment. It needs dependencies.

https://github.com/llvm/llvm-project/pull/161073