[llvm] [GitHub][CI] Add clang-tidy premerge workflow (PR #154829)

[Baranov Victor via llvm-commits]

vbvictor wrote:

> `code-lint-helper.py` currently very closely follows the structure of `code-format-helper.py`. I'm not convinced any of the abstractions there are actually useful, at least currently.

You suggest making it in "plain script" format without any abstractions?

https://github.com/llvm/llvm-project/pull/154829