PointGetPlan needs to resolve order by clause

[jackysp]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

create table t (i int key);
select * from t where i = 1 order by j limit 10;

2. What did you expect to see? (Required)

mysql> create table t (i int key);
Query OK, 0 rows affected (0.01 sec)

mysql> select * from t where i = 1 order by j limit 10;
ERROR 1054 (42S22): Unknown column 'j' in 'order clause'

3. What did you see instead (Required)

mysql> create table t (i int key);
Query OK, 0 rows affected (0.08 sec)

mysql> select * from t where i = 1 order by j limit 10;

4. What is your TiDB version? (Required)

c766530

[jackysp]

It should affect versions from v2.1 to v7.5.