MDEV-21117: refine the server binlog-based recovery for semisync

Problem:
=======
When the semisync master is crashed and restarted as slave it could
recover transactions that former slaves may never have seen.
A known method existed to clear out all prepared transactions
with --tc-heuristic-recover=rollback does not care to adjust
binlog accordingly.

Fix:
===
The binlog-based recovery is made to concern of the slave semisync role of
post-crash restarted server.
No changes in behavior is done to the "normal" binloggging server
and the semisync master.

When the restarted server is configured with
  --rpl-semi-sync-slave-enabled=1
the refined recovery attempts to roll back prepared transactions
and truncate binlog accordingly.
In case of a partially committed (that is committed at least
in one of the engine participants) such transaction gets committed.
It's guaranteed no (partially as well) committed transactions
exist beyond the truncate position.
In case there exists a non-transactional replication event
(being in a way a committed transaction) past the
computed truncate position the recovery ends with an error.

As after master crash and failover to slave, the demoted-to-slave
ex-master must be ready to face and accept its own (generated by)
events, without generally necessary --replicate-same-server-id.
So the acceptance conditions are relaxed for the semisync slave
to accept own events without that option.
While gtid_strict_mode ON ensures no duplicate transaction can be
(re-)executed the master_use_gtid=none slave has to be
configured with --replicate-same-server-id.

*NOTE* for reviewers.

This patch does not handle the user XA which is done
in next git commit.

mysql-test/suite/binlog/t/binlog_truncate_multi_engine.test

@@ -0,0 +1,60 @@
+# ==== Purpose ====
+#
+# Test verifies truncation of multiple binary logs with multiple transactional
+# storage engines
+#
+# ==== References ====
+#
+# MDEV-21117: recovery for --rpl-semi-sync-slave-enabled server
+
+--source include/have_rocksdb.inc
+--source include/have_innodb.inc
+--source include/have_debug.inc
+--source include/have_debug_sync.inc
+--source include/have_binlog_format_row.inc
+
+--let $old_max_binlog_size= `select @@global.max_binlog_size`
+call mtr.add_suppression("Can.t init tc log");
+call mtr.add_suppression("Aborting");
+--let $MYSQLD_DATADIR= `SELECT @@datadir`
+
+CREATE TABLE t1 (a INT PRIMARY KEY, b MEDIUMTEXT) ENGINE=Innodb;
+CREATE TABLE t2 (a INT PRIMARY KEY, b MEDIUMTEXT) ENGINE=rocksdb;
+
+--let $case = "A"
+--let $description = "neither engine committed => rollback & binlog truncate"
+# Hold off engine commits after write to binlog and its rotation.
+# The transaction is killed along with the server after that.
+--let $shutdown_timeout=0
+--let $debug_sync_action = "commit_after_release_LOCK_log SIGNAL con1_ready WAIT_FOR signal_no_signal"
+--let $restart_parameters = --rpl-semi-sync-slave-enabled=1
+--let $test_outcome= 1 row should be present in both tables; binlog is truncated; number of binlogs at reconnect - 3
+--source binlog_truncate_multi_engine.inc
+--echo Proof of the truncated binlog file is readable (two transactions must be seen):
+--exec $MYSQL_BINLOG --short-form --skip-annotate-row-events $MYSQLD_DATADIR/master-bin.000002
+
+--let $case = "B"
+--let $description = "one engine has committed its transaction branch"
+# Hold off after one engine has committed.
+--let $shutdown_timeout=0
+--let $debug_sync_action = ""
+# Both debug_sync and debug-dbug are required to make sure Engines remember the commit state
+# debug_sync alone will not help.
+--let $restart_parameters = --rpl-semi-sync-slave-enabled=1
+--let $test_outcome= 2 rows should be present in both tables; no binlog truncation; one extra binlog file compare with A; number of binlogs at reconnect - 4
+--source binlog_truncate_multi_engine.inc
+
+--let $case = "C"
+--let $description= "both engines have committed its transaction branch"
+--let $debug_sync_action = "commit_after_run_commit_ordered SIGNAL con1_ready WAIT_FOR signal_no_signal"
+# Hold off after both engines have committed. The server is shut down.
+--let $shutdown_timeout=
+--let $restart_parameters = --rpl-semi-sync-slave-enabled=1
+--let $test_outcome= 2 rows should be present in both tables; no binlog truncation; the same # of binlog files as in B; number of binlogs at reconnect - 4
+--source binlog_truncate_multi_engine.inc
+
+
+
+DROP TABLE t1, t2;
+
+--echo # End of the tests