The test was used to fail because of 
 UPDATE t3,t4 SET t3.a=t4.a + bug27417(1);
did not prescribe the order of two row operations implied by the update.

Fixed with forcing the order with adding a where condition w/o
affecting the former bug fixes logics.

mysql-test/extra/binlog_tests/mix_innodb_myisam_side_effects.test:
  implemented the bug page suggestion to make a test deterministic.
mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result:
  results are updated and (!) corrected.
mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result:
  results are updated