Preserve ExtParameterInfos into CGFunctionInfo.

As part of this, make the function-arrangement interfaces
a little simpler and more semantic.

NFC.

llvm-svn: 263191
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 051fa3c..4a0f149 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -2616,8 +2616,8 @@
   Args.push_back(&ArgData);
   Args.push_back(&ArgAddr);
 
-  const CGFunctionInfo &FI = CGM.getTypes().arrangeFreeFunctionDeclaration(
-      getContext().VoidTy, Args, FunctionType::ExtInfo(), /*variadic=*/false);
+  const CGFunctionInfo &FI =
+    CGM.getTypes().arrangeBuiltinFunctionDeclaration(getContext().VoidTy, Args);
 
   llvm::Function *F = llvm::Function::Create(
       llvm::FunctionType::get(VoidTy, {VoidPtrTy, VoidPtrTy}, false),