[clang] [Driver, test] Remove -v from mkdir & ln -s from a test since it fails on AIX (PR #72924)

[Liviu Ionescu via cfe-commits]

ilg-ul wrote:

Thank you @MaskRay for correcting the title and for the approval.

Please also merge it when possible.

https://github.com/llvm/llvm-project/pull/72924