cql3: expr: Add a test to show that std::forward is needed in expr::visit
cql3: expr: Add a test to show that std::forward is needed in expr::visit

Adds a test with a vistior that can only be used as a rvalue.
Without std::forward in expr::visit this test doesn't compile.

Signed-off-by: Jan Ciolek <b66a6f3989e26cb552db14b7ab163c3a50292e24@scylladb.com>

scylladb/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla