[llvm] Create build-llvm-for-windows.yaml (PR #153950)

[via llvm-commits]

ealcry wrote:

This pull request introduces a new GitHub Actions workflow to automate building LLVM for Windows. The workflow sets up a build environment, installs necessary dependencies, configures, builds LLVM using Ninja, and archives the build artifacts for later use.

Continuous integration and build automation:

* Added `.github/build-llvm-for-windows.yaml` workflow to automate the LLVM build process on Windows, including steps for environment setup, dependency installation, build configuration, compilation, and artifact archiving.

https://github.com/llvm/llvm-project/pull/153950