Reduce case and formalise into something we should be
able to use in mysql-test-run.

Index: ndb-work/mysql-test/t/ndb_bug26793.test
===================================================================


mysql-test/r/ndb_bug26793.result:
  BUG#26793 test: mysqld crashes in NDB on I_S query
mysql-test/t/ndb_bug26793.test:
  BUG#26793 test: mysqld crashes in NDB on I_S query