[clang] [CIR][NFC] Eliminate ArgInfo structure (PR #140612)

[Andy Kaylor via cfe-commits]

================
@@ -72,16 +68,15 @@ class RequiredArgs {
 
 class CIRGenFunctionInfo final
     : public llvm::FoldingSetNode,
-      private llvm::TrailingObjects<CIRGenFunctionInfo,
-                                    CIRGenFunctionInfoArgInfo> {
-  using ArgInfo = CIRGenFunctionInfoArgInfo;
-
+      private llvm::TrailingObjects<CIRGenFunctionInfo, CanQualType> {
----------------
andykaylor wrote:

Strictly speaking, that part of the buffer is used for both the return type and the argument types, but I agree that a comment would be useful.

https://github.com/llvm/llvm-project/pull/140612