[llvm] [polly] [IR] Add CallBr intrinsics support (PR #133907)

[Robert Imschweiler via llvm-commits]

ro-i wrote:

Regarding the Region/hasOnlySimpleTerminator comments: I think I should create another PR which solves this problem first, since it also applies to the regular inline-asm callbr when used for the amdgpu target. (I think I didn't know this at the time when I created this patch.)

https://github.com/llvm/llvm-project/pull/133907