[VectorCombine] Fix scalarizeExtExtract for big-endian#157962

RKSimon merged 6 commits intollvm:mainllvm/llvm-project:mainfrom

uyoyo0:vc/be-mapping-scalarize-extextractuyoyo0/llvm-project:vc/be-mapping-scalarize-extextractCopy head branch name to clipboard