[llvm] [Clang] Prevent `mlink-builtin-bitcode` from internalizing the RPC client (PR #118661)

[Joseph Huber via llvm-commits]

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@@ -233,6 +233,10 @@ bool InternalizePass::internalizeModule(Module &M) {
   else
     AlwaysPreserved.insert("__stack_chk_guard");
 
+  // For GPU host callbacks.
----------------
jhuber6 wrote:

```suggestion
  // Preserve the RPC interface for GPU host callbacks when internalizing.
```

https://github.com/llvm/llvm-project/pull/118661