[clang] [HLSL] Allow a groupshared struct to be passed as an implicit parameter (PR #229939)

[Helena Kotas via cfe-commits]

================
@@ -288,6 +298,8 @@ RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
       return MakeAddrLValue(ThisValue, Base->getType()->getPointeeType(),
                             BaseInfo, TBAAInfo);
     }
+    if (isa<HLSLOutArgExpr>(Base))
+      return HLSLThisLValue;
----------------
hekota wrote:

```suggestion
    if (HLSLThisLValue)
      return *HLSLThisLValue;
```

https://github.com/llvm/llvm-project/pull/229939