tests: Disable check_multi_schema for 'mc' format.
tests: Disable check_multi_schema for 'mc' format.

Altering types in schema has been disabled in Origin (see
CASSANDRA-12443). We do the same.

Signed-off-by: Vladimir Krivopalov <dc9186a06078733915a6fcbab34e59120be2b484@scylladb.com>

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