[RISCV] Use vleff's AVL when output VL doesn't dominate in RISCVVLOptimizer#156618

lukel97 merged 3 commits intollvm:mainllvm/llvm-project:mainfrom

lukel97:vloptimizer/vleff-avllukel97/llvm-project:vloptimizer/vleff-avlCopy head branch name to clipboard