expression: only wrap *_binary() builtin functions in new charset

[tangenta]

What problem does this PR solve?

Related to #30156.

Problem Summary:

drop table if exists t;
CREATE TABLE t (a CHAR(5) CHARACTER SET latin1);
INSERT INTO t VALUES (0xf6);
select * from t;
SELECT HEX(a) FROM t WHERE a= 0xf6;

In old version TiDB:

mysql> select * from t;
+------+
| a    |
+------+
| �     |
+------+
1 row in set (0.00 sec)

mysql> SELECT HEX(a) FROM t WHERE a= 0xf6;
+--------+
| HEX(a) |
+--------+
| F6     |
+--------+

In TiDB master:

mysql> select * from t;
+------+
| a    |
+------+
| �     |
+------+
1 row in set (0.00 sec)

mysql> SELECT HEX(a) FROM t WHERE a= 0xf6;
Empty set (0.01 sec)

Latin1 character set behavior should be consistent with the old version TiDB.

What is changed and how it works?

Only wrap from_binary() and to_binary() for the arguments with new charset.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

None

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[ti-chi-bot]

@tangenta: PR needs rebase.

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[tangenta]

The test will be added by #30288.