sstableloader: Ignore local and remote counter shards
sstableloader: Ignore local and remote counter shards

Our wormhole handling in scylla cannot deal with them anyway, and we
just create cql errors in driver that confuses the load process.

With this fix, the legacy migration tests in dtest pass once more, and
we can hopefully restore even old counter tables, as long as we get a
full set of the data (i.e. no missing sstables) and there was some
reconciliation of counters in the origin system.

Message-Id: <3f92171023d19486e243d1995cd1229d3e276bb6@scylladb.com>

scylladb/scylla-tools-java,scylladb/scylla-tools-java,scylladb/scylla-tools-java,scylladb/scylla-tools-java