Add missing override specifier [NFC]

This should fix a -Winconsistent-missing-override warning that is only
visible when Z3 is enabled.

llvm-svn: 356228

clang/lib/StaticAnalyzer/Core/Z3ConstraintManager.cpp

@@ -102,7 +102,7 @@ public:
       Z3_dec_ref(Context.Context, reinterpret_cast<Z3_ast>(Sort));
   }
 
-  void Profile(llvm::FoldingSetNodeID &ID) const {
+  void Profile(llvm::FoldingSetNodeID &ID) const override {
     ID.AddInteger(
         Z3_get_ast_id(Context.Context, reinterpret_cast<Z3_ast>(Sort)));
   }