[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/AST/OpenMPClause.cpp b/clang/lib/AST/OpenMPClause.cpp
index 5f9da85..87ab3e3 100644
--- a/clang/lib/AST/OpenMPClause.cpp
+++ b/clang/lib/AST/OpenMPClause.cpp
@@ -1964,3 +1964,7 @@
   TI.print(OS, Policy);
   return OS;
 }
+llvm::raw_ostream &clang::operator<<(llvm::raw_ostream &OS,
+                                     const OMPTraitInfo *TI) {
+  return TI ? OS << *TI : OS;
+}