MDEV-16172: Disable failing rpl tests

For some reason, two replication tests started failing intermittently
after commit 442a6e6b
changed the InnoDB version number from 5.7.21 to 10.3.7.
There is no obvious reference to INNODB_VERSION or
PLUGIN_AUTH_VERSION or PLUGIN_LIBRARY_VERSION in the replication tests.

mysql-test/suite/rpl/disabled.def

@@ -17,3 +17,5 @@ rpl_row_binlog_max_cache_size : MDEV-11092
 rpl_blackhole             : MDEV-11094
 rpl_row_mysqlbinlog       : MDEV-11095
 rpl_row_index_choice      : MDEV-11666
+rpl_parallel2             : fails after MDEV-16172
+rpl_semi_sync_after_sync  : fails after MDEV-16172