cql3: Handle subscript in multi_column_range_accumulator
cql3: Handle subscript in multi_column_range_accumulator

Same case as column_value.

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

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