token_restriction: Add non-token merge exception

Add exception that is thrown when merging of token and non-token 
restrictions is attempted. Before this change only merging non-token
and token restriction was validated (WHERE pk = 0 AND token(pk) > 0)
and not the other way (WHERE token(pk) > 0 AND pk = 0).

cql3/restrictions/token_restriction.hh

@@ -71,6 +71,11 @@ public:
     }
 
     void merge_with(::shared_ptr<restriction> restriction) override {
+        if (!has_token(restriction->expression)) {
+            throw exceptions::invalid_request_exception(
+                    format("Columns \"{}\" cannot be restricted by both a normal relation and a token relation",
+                            join(", ", get_column_defs())));
+        }
         expression = make_conjunction(std::move(expression), restriction->expression);
     }