BUG#59084: rpl_do_grant started to fail on FreeBSD (presumably after BUG#49978)

Problem: master executed a statement that would fail on slave
(namely, DROP USER 'create_rout_db'@'localhost').
Then the test did:
  --let $rpl_only_running_threads= 1
  --source include/rpl_reset.inc
rpl_reset.inc calls rpl_sync.inc, which first checks which of
the threads are running and then syncs those threads that are
running. If the SQL thread fails after the check, the sync will
fail. So there was a race in the test and it failed on some
slow hosts.
Fix: Don't replicate the failing statement.

mysql-test/suite/rpl/r/rpl_do_grant.result

@@ -162,7 +162,9 @@ USE bug42217_db;
 DROP FUNCTION upgrade_del_func;
 DROP FUNCTION upgrade_alter_func;
 DROP DATABASE bug42217_db;
+SET SQL_LOG_BIN= 0;
 DROP USER 'create_rout_db'@'localhost';
+SET SQL_LOG_BIN= 1;
 include/rpl_reset.inc
 USE test;
 ######## BUG#49119 #######

mysql-test/suite/rpl/t/rpl_do_grant.test

@@ -216,10 +216,10 @@ DROP DATABASE bug42217_db;
 -- connection master
 
 # user was already dropped in the slave before
-# so no need to wait for the slave to replicate
-# this statement (if it did and we later synced
-# the slave it would end up in an error anyway)
+# so we should not replicate this statement.
+SET SQL_LOG_BIN= 0;
 DROP USER 'create_rout_db'@'localhost';
+SET SQL_LOG_BIN= 1;
 
 # finish entire clean up (remove binlogs)
 # so that we leave a pristine environment for the