[RISCV] Re-work how VWADD_W_VL and similar _W_VL nodes are handled in combineOp_VLToVWOp_VL.#159205

topperc merged 4 commits intollvm:mainllvm/llvm-project:mainfrom

topperc:pr/combineOp_VLToVWOp_VLtopperc/llvm-project:pr/combineOp_VLToVWOp_VLCopy head branch name to clipboard