sstables: set _single_partition_read for single parititon reads
sstables: set _single_partition_read for single parititon reads

duarten/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,duarten/scylla,avikivity/scylla,avikivity/scylla,scylladb/scylla,duarten/scylla,scylladb/scylla