[clang] [clang-tools-extra] [llvm] [llvm][support] Move `make_absolute` from `sys::fs` to `sys::path` (PR #161459)

[Steven Wu via llvm-commits]

cachemeifyoucan wrote:

> Do you have an example? I only see the one-argument make_absolute, which is still in fs:: because it implicitly uses the current working directory.

Ah. There are two versions. Then it is actually a bit confusing that they are in different namespaces but with same name. It might be nice to further distinguish them with different name but I don't have good suggestions. 

https://github.com/llvm/llvm-project/pull/161459