Create build-llvm-for-windows.yaml

[ealcry]

build llvm via github-action

[github-actions]

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[ealcry]

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.