[llvm] [X86][SimplifyCFG] Support hoisting load/store with conditional faulting (PR #96878)

[Shengchen Kan via llvm-commits]

KanRobert wrote:

> I think you need at least one backend test case to show this change? (llc also runs SimplifyCFG)

Hmm, how to let llc run simplifycfg? @DianQK  I can't find simplifycfg in the log of `print-after-all`. 

If I add ` -start-before=simplifycfg` to the flags, it will crash. (not related this PR)
```
bash$ cat 1.c
void f() {}

bash$ clang -O2 1.c -S -emit-llvm

bash$ llc --start-before=simplifycfg <1.ll

Assertion `!NodePtr->isKnownSentinel()' failed
```

https://github.com/llvm/llvm-project/pull/96878