[OpenACC] Fix memory leak for recipe list in Reduction (llvm#163219)

After misunderstanding what was going on in the ASAN patches, I finally
realize I just missed a call to a destructor! This patch ensures that
the Recipe is deleted properly with the AST.

Author: erichkeane

clang/include/clang/AST/OpenACCClause.h

@@ -1325,17 +1325,17 @@ class OpenACCReductionClause final
         Op(Operator) {
           assert(VarList.size() == Recipes.size());
     setExprs(getTrailingObjects<Expr *>(VarList.size()), VarList);
+    llvm::uninitialized_copy(Recipes,
+                             getTrailingObjects<OpenACCReductionRecipe>());
+  }
 
-    // Initialize the recipe list.
-    unsigned I = 0;
-    for (const OpenACCReductionRecipe &R : Recipes) {
-      new (&getTrailingObjects<OpenACCReductionRecipe>()[I])
-          OpenACCReductionRecipe(R);
-      ++I;
+public:
+  ~OpenACCReductionClause() {
+    for (unsigned I = 0; I < getExprs().size(); ++I) {
+      getTrailingObjects<OpenACCReductionRecipe>()[I].~OpenACCReductionRecipe();
     }
   }
 
-public:
   static bool classof(const OpenACCClause *C) {
     return C->getClauseKind() == OpenACCClauseKind::Reduction;
   }