[llvm] [Support/rpmalloc] Updated fake atomics with Interlocked functions (PR #148303)

[Dmitry Vasilyev via llvm-commits]

slydiman wrote:

> We do require VS 2019 version 16.8 minimally in LLVM, please see [28bba0d](https://github.com/llvm/llvm-project/commit/28bba0d717a43ea3f01689625577197889374965)
> 
> However that is not enough afaik for C11 stdatomics, it needs VS 2022 version 17.5 minimally: https://devblogs.microsoft.com/cppblog/c11-atomics-in-visual-studio-2022-version-17-5-preview-2/

Nice point.

> One other option would be to integrate into LLVM from [develop](https://github.com/mjansson/rpmalloc/tree/develop) at head (if you think that should be stable enough).

But the develop branch of rpmalloc uses only stdatomic since 2023.
So we cannot use any new release or dev branch as is until LLVM will require VS 2022.

https://github.com/llvm/llvm-project/pull/148303