fixes in test results (using # for positions in SHOW BINLOG EVENTS).

mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test:
  As in other tests, we should replace both position columns of SHOW BINLOG
  EVENTS; otherwise a small change (like here, the fact that CREATE TEMPORARY
  TABLE is not binlogged in RBR as a consequence of the bugfix for BUG#20522)
  causes a large diff in the result file.
mysql-test/r/binlog_row_mix_innodb_myisam.result:
  result update: positions in SHOW BINLOG EVENTS become #, and
  the CREATE TEMPORARY TABLE disappear from binlog (consequence of fix for
  BUG#20522 "RBR: CREATE TEMPORARY TABLE SELECT writes to binlog though
  unneeded").