MDEV-32168: slave_error_param condition is never checked from the wait_for_slave_param.inc

Test rpl.show_status_stop_slave_race-7126 now fails sporadically
because it is expected to sometimes (but not always) leave an error
condition after slave stop. Fix by explicitly allowing the error
condition in this case.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

mysql-test/include/wait_for_slave_io_to_stop.inc

@@ -21,6 +21,14 @@
 #   $slave_timeout
 #     See include/wait_for_slave_param.inc.
 #
+#   $rpl_allow_error
+#     By default, this file fails if there is an error in the IO
+#     thread. However, if an error in the IO thread is possible and allowed,
+#     setting $rpl_allow_error=1 will prevent this file from failing if
+#     there is an error in the IO thread.
+#     (If an error is _always_ expected, a better alternative might be to
+#     use wait_for_slave_io_error.inc instead of this file).
+#
 #   $rpl_debug
 #     See include/rpl_init.inc
 
@@ -31,7 +39,10 @@
 
 --let $slave_param= Slave_IO_Running
 --let $slave_param_value= No
---let $slave_error_param= Last_IO_Errno
+if (!$rpl_allow_error)
+{
+  --let $slave_error_param= Last_IO_Errno
+}
 --source include/wait_for_slave_param.inc
 --let $slave_error_param=
 

mysql-test/include/wait_for_slave_sql_to_stop.inc

@@ -21,6 +21,14 @@
 #   $slave_timeout
 #     See include/wait_for_slave_param.inc
 #
+#   $rpl_allow_error
+#     By default, this file fails if there is an error in the SQL
+#     thread. However, if an error in the SQL thread is possible and allowed,
+#     setting $rpl_allow_error=1 will prevent this file from failing if
+#     there is an error in the SQL thread.
+#     (If an error is _always_ expected, a better alternative might be to
+#     use wait_for_slave_sql_error.inc instead of this file).
+#
 #   $rpl_debug
 #     See include/rpl_init.inc
 
@@ -31,7 +39,10 @@
 
 --let $slave_param= Slave_SQL_Running
 --let $slave_param_value= No
---let $slave_error_param= Last_SQL_Errno
+if (!$rpl_allow_error)
+{
+  --let $slave_error_param= Last_SQL_Errno
+}
 --source include/wait_for_slave_param.inc
 --let $slave_error_param= 
 

mysql-test/suite/rpl/t/show_status_stop_slave_race-7126.test

@@ -15,6 +15,9 @@ call mtr.add_suppression("Master is configured to log replication events");
 # All done.
 
 --connection slave
+# The parallel START SLAVE can leave an error condition if the last START was
+# aborted by the master due to conflicting server_id from multiple connections.
+--let $rpl_allow_error= 1
 --source include/wait_for_slave_to_stop.inc
 start slave;