[clang] [Win/X86] Make _m_prefetch[w] builtins to avoid winnt.h conflicts (PR #115099)

[Hans Wennborg via cfe-commits]

zmodem wrote:

The build is still broken (e.g. https://lab.llvm.org/buildbot/#/builders/63/builds/3861). I'll back it out.

https://github.com/llvm/llvm-project/pull/115099