[llvm] [GlobalOpt] Don't replace aliasee with alias that has weak linkage (PR #91483)

[Eli Friedman via llvm-commits]

https://github.com/efriedma-quic commented:

I'm having trouble following all the different cases interleaved together.  I just spent half an hour trying to follow this, and I feel like I understand less than when I started.

Please delete the `Ret` variable, and replace the corresponding logic with something actually comprehensible.

https://github.com/llvm/llvm-project/pull/91483