[clang] [WIP][Modules] Delay deserialization of preferred_name attribute at r… (PR #122726)

[Ilya Biryukov via cfe-commits]

================
@@ -1205,6 +1205,12 @@ class ASTReader
   /// been completed.
   std::deque<PendingDeclContextInfo> PendingDeclContextInfos;
 
+  struct PendingPreferredNameAttribute {
----------------
ilya-biryukov wrote:

NIT: there's nothing specific to `PreferredName` her, could we just call it `DeferredAttribute`?
(Same for functions that have it as a substring)

https://github.com/llvm/llvm-project/pull/122726