Revert "[FIX] Do not copy an llvm::function_ref if it has to be reused"

This fix doesn't seem to be right (function_ref can/should be passed by
value) so I'm reverted it to see if the buildbots decide to explain
what's wrong.

This reverts commit 857bf5d.

Author: dwblaikie

clang/include/clang/AST/OpenMPClause.h

@@ -7060,10 +7060,10 @@ struct OMPTraitInfo {
   llvm::SmallVector<OMPTraitSet, 4> Sets;
 
   bool anyScoreOrCondition(
-      const llvm::function_ref<bool(Expr *&, bool /* IsScore */)> &Cond) {
-    return llvm::any_of(Sets, [&Cond](OMPTraitInfo::OMPTraitSet &Set) {
+      llvm::function_ref<bool(Expr *&, bool /* IsScore */)> Cond) {
+    return llvm::any_of(Sets, [Cond](OMPTraitInfo::OMPTraitSet &Set) {
       return llvm::any_of(
-          Set.Selectors, [&Cond](OMPTraitInfo::OMPTraitSelector &Selector) {
+          Set.Selectors, [Cond](OMPTraitInfo::OMPTraitSelector &Selector) {
             return Cond(Selector.ScoreOrCondition,
                         /* IsScore */ Selector.Kind !=
                             llvm::omp::TraitSelector::user_condition);