that was already analyzed by Oracle: EXPLAIN can return 3 or 4 in "rows"; using replace_column to work around this.

mysql-test/include/index_merge2.inc:
  replace "rows" column of some EXPLAINs by "#", if told so
mysql-test/r/index_merge_innodb.result:
  result update
mysql-test/t/index_merge_innodb.test:
  tell index_merge2.inc to accept random "rows" values in some EXPLAINs; we don't do this in index_merge_myisam.test
  which has no randomness here.