[llvm] [utils] Add an alias name --cc for --clang (PR #69442)

[Fangrui Song via llvm-commits]

MaskRay wrote:

> I don't really see any need for this alias (I always use a wrapper script that passes the right arguments), but I don't see it doing any harm either so it seems fine to me.

I don't really see any need for this alias as well. Perhaps we should not add it.

https://github.com/llvm/llvm-project/pull/69442