[clang] [Clang] Fix handling of pack indexing types in constraints of redeclaration (PR #139057)

[Younan Zhang via cfe-commits]

================
@@ -76,9 +77,18 @@ enum class TemplateSubstitutionKind : char {
   class MultiLevelTemplateArgumentList {
     /// The template argument list at a certain template depth
 
+    enum ListProperties {
+      /// A 'Final' substitution means that Subst* nodes won't be built
+      /// for the replacements.
+      IsFinal = 0x1,
----------------
zyn0217 wrote:

This is not true because Final flag is placed on the Subst* nodes now

https://github.com/llvm/llvm-project/pull/139057