[llvm] [NFC][LoopInfo] Remove redundant LLVM_ABI from Loop member functions (PR #195863)

[Adel Ejjeh via llvm-commits]

adelejjeh wrote:

> LLM seems a bit overkill to delete 20 characters.

I mainly used it for the busy work (creating branch/worktree, committing/pushing to fork, running check-llvm, opening PR).

https://github.com/llvm/llvm-project/pull/195863