Scylla server can't read sstables that were created
with different partitioner than the one being used by Scylla.
We should make sure that Scylla identifies such mismatch
and refuses to use such SSTables.
We can use partitioner information stored in validation metadata
(Statistics.db file) for each SSTable and compare it against
partitioner used by Scylla.
Fixes#4331
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>