[llvm] [Github] Add Zlib at build time to CI container (PR #123489)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

>  Is there a plan to fix the test too?

This fixes the test. I want to fix the requires in the test too so it actually checks for what it needs, but putting that on the back-burner for now.

https://github.com/llvm/llvm-project/pull/123489