[clang] fix serialization of SubstNonTypeTemplateParmExpr (#134560)

This fixes a couple of mistakes introduced when merging
#132748

Fixes msan failure reported here:
#132748 (comment)

Author: mizvekov

clang/lib/AST/ASTContext.cpp

@@ -7011,7 +7011,7 @@ TemplateName ASTContext::getCanonicalTemplateName(TemplateName Name,
         getCanonicalTemplateArgument(subst->getArgumentPack());
     return getSubstTemplateTemplateParmPack(
         canonArgPack, subst->getAssociatedDecl()->getCanonicalDecl(),
-        subst->getFinal(), subst->getIndex());
+        subst->getIndex(), subst->getFinal());
   }
   case TemplateName::DeducedTemplate: {
     assert(IgnoreDeduced == false);

clang/lib/Serialization/ASTReaderStmt.cpp

@@ -2229,6 +2229,7 @@ void ASTStmtReader::VisitSubstNonTypeTemplateParmExpr(
     E->PackIndex = Record.readInt();
   else
     E->PackIndex = 0;
+  E->Final = CurrentUnpackingBits->getNextBit();
   E->SubstNonTypeTemplateParmExprBits.NameLoc = readSourceLocation();
   E->Replacement = Record.readSubExpr();
 }

clang/lib/Serialization/ASTWriterStmt.cpp

@@ -2229,6 +2229,7 @@ void ASTStmtWriter::VisitSubstNonTypeTemplateParmExpr(
   CurrentPackingBits.addBit((bool)E->getPackIndex());
   if (auto PackIndex = E->getPackIndex())
     Record.push_back(*PackIndex + 1);
+  CurrentPackingBits.addBit(E->getFinal());
 
   Record.AddSourceLocation(E->getNameLoc());
   Record.AddStmt(E->getReplacement());