[clang] [clang][ssaf][NFC] Rename ssaf-linker tool to clang-ssaf-linker (PR #185631)

[Nico Weber via cfe-commits]

nico wrote:

> Personally, I didn't feel it's necessary because `clang` is already present in the path name - but we could come back and rename the directory sure. I'll come back to address this.

`clang-sycl-linker` seem pretty similar name-wise and it's in clang/tools/clang-sycl-linker. Might be nice if things were consistent?

(But I don't feel all that strongly.)

https://github.com/llvm/llvm-project/pull/185631