[llvm] [CodeGen][CodeLayout] Fix segfault on access to deleted block in MBP. (PR #142357)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> > Did you try llvm-reduce on it?
> 
> Yes. No effect.
> 
> I've spent ~1 day in different attempts to reduce the test case =)

Did you try llvm-reduce on the MIR?

https://github.com/llvm/llvm-project/pull/142357