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

[Afanasyev Ivan via llvm-commits]

ivafanas wrote:

PR is ready for review.

Seems like flang test is flaky. I've failed to reproduce the problem locally and it disappeared after rerun.

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