Merge 10.5 into 10.6

mysql-test/main/null_key.test

@@ -237,11 +237,13 @@ EXPLAIN SELECT SQL_CALC_FOUND_ROWS * FROM t1 LEFT JOIN t2 ON t1.a=t2.a
                                              LEFT JOIN t3 ON t2.b=t3.b;
 FLUSH STATUS ;
 --disable_ps2_protocol
+--disable_cursor_protocol
 SELECT SQL_CALC_FOUND_ROWS * FROM t1 LEFT JOIN t2 ON t1.a=t2.a
                                      LEFT JOIN t3 ON t2.b=t3.b;
 
 --disable_view_protocol
 SELECT FOUND_ROWS();
+--enable_cursor_protocol
 SHOW STATUS LIKE "handler_read%";
 --enable_view_protocol
 --enable_ps2_protocol