[DAG] visitEXTRACT_SUBVECTOR - change fold helper methods to take operands instead of EXTRACT_SUBVECTOR node. NFC.#138279

RKSimon merged 2 commits intollvm:mainllvm/llvm-project:mainfrom

RKSimon:dag-extract-subvector-foldsRKSimon/llvm-project:dag-extract-subvector-foldsCopy head branch name to clipboard