[llvm] [BranchFolding] Fix assertion failure in HoistCommonCodeInSuccs (PR #141028)

[Mikael Holmén via llvm-commits]

mikaelholmen wrote:

> Looks good; however I'm not familiar with ARM assembly for the test, @mikaelholmen would you be able to confirm the output is alright?

I've no idea about ARM either, but I can confirm that the patch fixes the crash I saw for our downstream target.

The ARM reproducer was just something I crafted from a minimal mir-reproducer for our target to have an in-tree reproducer for the crash.

https://github.com/llvm/llvm-project/pull/141028