[clang] [clang] Support --sysroot= for ${arch}-windows-msvc targets (PR #96417)

[via cfe-commits]

trcrsired wrote:

@zmodem Can you review it again? I have removed the formatting part here. Although I disagree with -stdlib=msstl thing. Can you check any other part that is problematic first?

https://github.com/llvm/llvm-project/pull/96417