[SLP] NFC. Remove the redundant MainOp and AltOp find process.#133642

HanKuanChen merged 1 commit intollvm:mainllvm/llvm-project:mainfrom

HanKuanChen:slp-nfc-SplitVectorizeHanKuanChen/llvm-project:slp-nfc-SplitVectorizeCopy head branch name to clipboard