[llvm] [X86]: Rewrite demorgan rule for ANDN (PR #163789)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon requested changes to this pull request.

```
Failed Tests (4):
  LLVM :: CodeGen/LoongArch/ctlz-cttz-ctpop.ll
  LLVM :: CodeGen/PowerPC/xxeval-and-nand.ll
  LLVM :: CodeGen/SystemZ/scalar-ctlz-02.ll
  LLVM :: CodeGen/SystemZ/vec-eval.ll
```

https://github.com/llvm/llvm-project/pull/163789