cql3/statements/create_index_statement: Add materialized view to validate()
cql3/statements/create_index_statement: Add materialized view to validate()

Apache Cassandra does not support secondary indices on materialized
views so neither should we.

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