[llvm] [SandboxIR] Add Instruction::isStackSaveRestoreIntrinsic() and isMemDepCandidate() (PR #109212)

[Arthur Eubanks via llvm-commits]

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@@ -1943,6 +1945,26 @@ class Instruction : public sandboxir::User {
   /// LangRef.html for the meaning of these flags.
   void copyFastMathFlags(FastMathFlags FMF);
 
+  bool isStackSaveRestoreIntrinsic() const {
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aeubanks wrote:

```suggestion
  bool isStackSaveOrRestoreIntrinsic() const {
```

https://github.com/llvm/llvm-project/pull/109212