[llvm] [cmake] Set up llvm-ml as ASM_MASM tool in WinMsvc.cmake (PR #104903)

[Martin Storsjö via llvm-commits]

mstorsjo wrote:

CC @nga888 

Hmm, while this does fix building, I've understood that it actually doesn't work correctly at runtime, see https://github.com/llvm/llvm-project/issues/54773 and #107618.

Not sure - should we revert this in the meantime, until a working llvm-ml exists, or should we just keep it - as things will get fixed eventually?

https://github.com/llvm/llvm-project/pull/104903