[llvm] [nsan] Fix `Wstring-conversion` error (PR #100328)

[Yingwei Zheng via llvm-commits]

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@@ -527,7 +527,7 @@ NsanMemOpFn::NsanMemOpFn(Module &M, ArrayRef<StringRef> Sized,
         M.getOrInsertFunction(Fallback, Attr, VoidTy, PtrTy, IntptrTy));
     SizedFnTy = FunctionType::get(VoidTy, {PtrTy}, false);
   } else {
-    assert(!"Unexpected value of sized functions arguments");
+    assert(0 && "Unexpected value of sized functions arguments");
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dtcxzyw wrote:

```suggestion
    llvm_unreachable("Unexpected value of sized functions arguments");
```

https://github.com/llvm/llvm-project/pull/100328