Added test case for MDEV-15742 to prove that it works

MDEV-15742 Assertion `table_share->tmp_table != NO_TMP_TABLE ||
m_lock_type == 1' failed in handler::ha_write_row

mysql-test/suite/sql_sequence/lock.result

@@ -17,3 +17,13 @@ a
 select * from t2;
 a
 drop tables s1, t1, t2;
+CREATE SEQUENCE s1;
+LOCK TABLE s1 READ;
+SELECT NEXTVAL(s1);
+ERROR HY000: Table 's1' was locked with a READ lock and can't be updated
+SELECT NEXTVAL(s);
+ERROR HY000: Table 's' was not locked with LOCK TABLES
+DROP SEQUENCE s1;
+ERROR HY000: Table 's1' was locked with a READ lock and can't be updated
+unlock tables;
+DROP SEQUENCE s1;

mysql-test/suite/sql_sequence/lock.test

@@ -22,3 +22,19 @@ unlock tables;
 select * from t1;
 select * from t2;
 drop tables s1, t1, t2;
+
+#
+# MDEV-15742 Assertion `table_share->tmp_table != NO_TMP_TABLE ||
+# m_lock_type == 1' failed in handler::ha_write_row
+#
+
+CREATE SEQUENCE s1;
+LOCK TABLE s1 READ;
+--error ER_TABLE_NOT_LOCKED_FOR_WRITE
+SELECT NEXTVAL(s1);
+--error ER_TABLE_NOT_LOCKED
+SELECT NEXTVAL(s);
+--error ER_TABLE_NOT_LOCKED_FOR_WRITE
+DROP SEQUENCE s1;
+unlock tables;
+DROP SEQUENCE s1;