[llvm] [InitUndef] Enable the InitUndef pass on all targets (PR #108353)

[Nikita Popov via llvm-commits]

nikic wrote:

If this is undesirable for AMDGPU, I can restore the target hook. A caveat is that I think this is always required for inline asm (because we have no knowledge over whether it's safe or not in that case), but if needed we could explicitly check for that case separately from the rest.

https://github.com/llvm/llvm-project/pull/108353