[llvm] [BOLT][AArch64] Handle OpNegateRAState to enable optimizing binaries with pac-ret hardening (PR #120064)

[Paschalis Mpeis via llvm-commits]

================
@@ -273,6 +275,11 @@ static cl::opt<bool> ShortenInstructions("shorten-instructions",
                                          cl::desc("shorten instructions"),
                                          cl::init(true),
                                          cl::cat(BoltOptCategory));
+
+cl::opt<bool> AllowPacret(
+    "allow-experimental-pacret",
+    cl::desc("Enable processing binaries with pac-ret (experimental)"),
+    cl::cat(BoltOptCategory));
----------------
paschalis-mpeis wrote:

I get some linking error:

```
ld.lld: error: undefined symbol: opts::AllowPacret
```

Can you move this to `CommandLineOptions.cpp` ?

Might also worth being explicit on how it's initialized with `cl::init(false)`

https://github.com/llvm/llvm-project/pull/120064