[Utils] Consolidate `LockstepReverseIterator` into own header (NFC)#116657

dwblaikie merged 3 commits intollvm:mainllvm/llvm-project:mainfrom

antoniofrighetto:feature/move-lri-in-utilsantoniofrighetto/llvm-project:feature/move-lri-in-utilsCopy head branch name to clipboard