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

[Robert Imschweiler via llvm-commits]

ro-i wrote:

According to the feedback I received, I decided to split the PR up. I will first have some PRs* to add basic inline-asm support for the AMDGPU backend (which didn't exist before) and then I'll stack this PR on top of them so that it can be solely focused on adding intrinsic support to the callbr instruction without having to add support for callbr, too.

*The first PR of this series is https://github.com/llvm/llvm-project/pull/149308

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