cql3: expr: extract get_value(subscript) from get_value(column_maybe_subscripted)
cql3: expr: extract get_value(subscript) from get_value(column_maybe_subscripted)

We wish to wire get_value(subscript) into evaluate (and get rid of
column_maybe_subscripted).

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