[flang] [llvm] [mlir] [Flang]Fix for changed code at the end of AllocaIP. (PR #92430)

[Kiran Chandramohan via llvm-commits]

kiranchandramohan wrote:

> Ideally, the only thing added to the alloca block are allocas. Apparently in this case something is splitting the alloca block before the AllocaIP, do you know what exactly?

One possible reason is that for allocatable variables the privatization demands that we allocate only if the original variable is allocated. This introduces an `if` and hence multiple blocks.

https://github.com/llvm/llvm-project/pull/92430