[LoongArch][DAGCombiner] Combine vand (vnot ..) to vandn#161037

ylzsx wants to merge 5 commits intousers/ylzsx/precommit-andn-combinellvm/llvm-project:users/ylzsx/precommit-andn-combinefrom

users/ylzsx/andn-combinellvm/llvm-project:users/ylzsx/andn-combineCopy head branch name to clipboard