[llvm] [IR] Don't store switch case values as operands (PR #166842)

[Vitaly Buka via llvm-commits]

vitalybuka wrote:

Actually it looks more complicated.
It does not reproduce on 1 stage build.
Only 2 stages, when the 1st stage includes the patch, it's going to break those tests.

Here instruction how to reproduce the bot:
https://github.com/google/sanitizers/wiki/SanitizerBotReproduceBuild

But probably any 2 stages should work.

https://github.com/llvm/llvm-project/pull/166842