[llvm] [Instruction] Add missing implementation for `moveAfter(InstListType::iterator)` (PR #143093)

[Tobias Kamm via llvm-commits]

kammt wrote:

This is my first PR here, so I don't have commit access (nor see an option here to merge the PR, as there usually is). So would be great if you could do that for me!

https://github.com/llvm/llvm-project/pull/143093