MDEV-5419 no audit events for warnings converted to errors in the strict mode.

Plugins get error notifications only when my_message_sql() is called.
        But errors are launched with THD::raise_condition() calls in other
        places. These are push_warning(), implementations of SIGNAL and
        RESIGNAL commands.
        So it makes sence to notify plugins there in THD::raise_condition().

mysql-test/suite/plugins/t/sql_error_log.test

@@ -0,0 +1,55 @@
+
+--source include/not_embedded.inc
+
+if (!$SQL_ERRLOG_SO) {
+  skip No SQL_ERROR_LOG plugin;
+}
+
+--disable_warnings
+drop procedure if exists test_error;
+drop table if exists t1;
+--enable_warnings
+
+install plugin SQL_ERROR_LOG soname 'sql_errlog';
+
+show variables like 'sql_error_log%';
+set global sql_error_log_rate=1;
+--error ER_NO_SUCH_TABLE
+select * from t_doesnt_exist;
+--error 1064
+syntax_error_query;
+
+delimiter |;
+
+CREATE PROCEDURE test_error()
+BEGIN
+DECLARE CONTINUE HANDLER
+FOR 1146
+BEGIN
+RESIGNAL SQLSTATE '40000' SET
+MYSQL_ERRNO = 1000,
+MESSAGE_TEXT = 'new message';
+END;
+SELECT `c` FROM `temptab`;
+END|
+
+delimiter ;|
+
+--error 1000
+CALL test_error();
+drop procedure test_error;
+
+SET SQL_MODE = STRICT_ALL_TABLES;
+create table t1(id int);
+--error 1366
+insert into t1 values ('aa');
+SET SQL_MODE = '';
+drop table t1;
+
+uninstall plugin SQL_ERROR_LOG;
+
+let $MYSQLD_DATADIR= `SELECT @@datadir`;
+# replace the timestamp and the hostname with constant values
+--replace_regex /[1-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9] [0-9][0-9]:[0-9][0-9]:[0-9][0-9] [^E]*/TIME HOSTNAME /
+cat_file $MYSQLD_DATADIR/sql_errors.log;
+