[NFC][clang] Fix static analyzer concerns

DelegatingDeserializationListener frees resources in the destructor but doesn't
have user-written copy c'tor or assignment operator, so copying it using
default ones can cause double free.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D156405

clang/lib/Frontend/FrontendAction.cpp

@@ -61,6 +61,11 @@ public:
       delete Previous;
   }
 
+  DelegatingDeserializationListener(const DelegatingDeserializationListener &) =
+      delete;
+  DelegatingDeserializationListener &
+  operator=(const DelegatingDeserializationListener &) = delete;
+
   void ReaderInitialized(ASTReader *Reader) override {
     if (Previous)
       Previous->ReaderInitialized(Reader);