executor: correct range calculation for CHAR column

[zz-jason]

What problem does this PR solve?

fix the wrong range calculation for:

• point get char[n], char[n] binary, binary[n] column
• index lookup char[n], char[n] binary, binary[n] column

This PR can:

• close Incorrect range for CHAR column #10397
• close Incorrect range for CHAR BINARY column #10398

What is changed and how it works?

specially handle the "PAD_CHAR_TO_FULL_LENGTH" for char column.

Check List

Tests

• Unit test

Related changes

• Need to cherry-pick to the release branch
• Need to be included in the release note

[zz-jason]

/run-all-tests

[zz-jason]

/run-integration-common-test
/run-unit-test

[XuHuaiyu]

Please check:

create table t(a binary(2) primary key, b char(2));
insert into t values("a ", "b");
insert into t values("a", "b");
select * from t where a = "a ";

MySQL:

mysql> select * from t where a = "a ";
+----+------+
| a  | b    |
+----+------+
| a  | b    |
+----+------+
1 row in set (0.00 sec)

TiDB:

tidb> select * from t where a = "a ";
Empty set (0.00 sec)

tidb> desc select * from t where a = "a ";
+-------------+-------+------+------------------+
| id          | count | task | operator info    |
+-------------+-------+------+------------------+
| Point_Get_1 | 1.00  | root | table:t, index:a |
+-------------+-------+------+------------------+
1 row in set (0.00 sec)

[zz-jason]

/rebuild

[zz-jason]

/run-all-tests

[zz-jason]

/run-mybatis-test

[codecov]

Codecov Report

Merging #10124 into master will increase coverage by 0.0144%.
The diff coverage is 89.855%.

@@               Coverage Diff                @@
##             master     #10124        +/-   ##
================================================
+ Coverage   77.3299%   77.3444%   +0.0144%     
================================================
  Files           412        412                
  Lines         86546      86566        +20     
================================================
+ Hits          66926      66954        +28     
+ Misses        14486      14479         -7     
+ Partials       5134       5133         -1

[zz-jason]

/run-all-tests

[XuHuaiyu]

LGTM

[alivxxx]

LGTM