[llvm] Revert "[AIX] Remove unsupported AIX native echo option -n (llvm#199079)" (PR #199277)

[Fangrui Song via llvm-commits]

MaskRay wrote:

> @MaskRay Do I only need to change the description on the PR or do I need to add it to the commit message as well? (Note: I have changed it now for PR description)

Just update the PR description, which will be used as the default commit message. The commit messages in the commits are completely ignored.

https://github.com/llvm/llvm-project/pull/199277