[llvm] [AIX] Support per global code model. (PR #79202)

[Amy Kwan via llvm-commits]

================
@@ -72,8 +74,22 @@ class MCSymbolXCOFF : public MCSymbol {
 
   void setEHInfo() const { modifyFlags(SF_EHInfo, SF_EHInfo); }
 
+  bool hasPerSymbolCodeModel() const { return PerSymbolCodeModel.has_value(); }
+
+  CodeModel getPerSymbolCodeModel() const {
+    assert(hasPerSymbolCodeModel() &&
+           "Requested codemodel for symbol with out one");
----------------
amy-kwan wrote:

nit:
```suggestion
           "Requested code model for symbol without one");
```

https://github.com/llvm/llvm-project/pull/79202