Reason:
   This test executes DML statements on a NDB table to detect if some SQL statements of special interest commits the ongoing transaction.
   When running in MIXED mode, automatic switching from statement-based to row-based replication takes place when a DML statement
   updates an NDB table.
   That means running this test on NDB with binlog-format=mixed and binlog-format=row mostly checks the same routines twice.
   Therefore we skip the variant with binlog-format=mixed.