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

[Alexandre Ganea via llvm-commits]

aganea wrote:

Maybe extend the commit description, to explain the situation: ie. LLVM is on VS 2019 version 16.7 currently and eventually we require VS 2022 if we wanted to use stdatomics in rpmalloc, etc. In the meanwhile, we use the Interlockeds intrinsics when building with MSVC.

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