test/boost/multishard_mutation_query_test: add read_all_partitions_one_by_one() overload with slice
test/boost/multishard_mutation_query_test: add read_all_partitions_one_by_one() overload with slice

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