[llvm] [BranchFolding] Kill common hoisted debug instructions (PR #140091)

[Orlando Cazalet-Hyams via llvm-commits]

OCHyams wrote:

> LLVM Buildbot has detected a new failure on builder `clang-hip-vega20` running on `hip-vega20-0` while building `llvm` at step 3 "annotate".
> 
> Full details are available at: https://lab.llvm.org/buildbot/#/builders/123/builds/23775
> 
> Here is the relevant piece of the build log for the reference

Not exactly sure what this bot is testing, or how my change is interacting with it. It looks like it goes green a few builds after this though, so possibly just flaky.

https://github.com/llvm/llvm-project/pull/140091