[OpenMP][NFC] Minimize memory usage and copying of `OMPTraitInfo`s

See rational here: https://reviews.llvm.org/D71830#1922656

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D76173
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 9ccebae..f308246 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -6624,9 +6624,9 @@
   Record.AddSourceLocation(C->getKindKwLoc());
 }
 
-void ASTRecordWriter::writeOMPTraitInfo(const OMPTraitInfo &TI) {
-  writeUInt32(TI.Sets.size());
-  for (const auto &Set : TI.Sets) {
+void ASTRecordWriter::writeOMPTraitInfo(const OMPTraitInfo *TI) {
+  writeUInt32(TI->Sets.size());
+  for (const auto &Set : TI->Sets) {
     writeEnum(Set.Kind);
     writeUInt32(Set.Selectors.size());
     for (const auto &Selector : Set.Selectors) {