[llvm] Update Windows release script (PR #215749)

[Oliver Old via llvm-commits]

oold wrote:

Just a few things I'd like to add. First of all, I just got a notification this [action](https://github.com/llvm/llvm-project/actions/runs/31575396585) failed. Second, I've been thinking about converting the build script into a Python script at some point. I'd like to know whether that's a desirable change. And finally, I've had some issues running the release build script locally, where the build failed with undeclared identifier errors in OpenMP. Not quite sure what is missing on my system.

https://github.com/llvm/llvm-project/pull/215749