Function to_utf8 supports char type

[borderlayout]

Description

Function to_utf8 doesn't support char type. When this function is applied to the char type in Hive, an error will be reported. This PR modifies to_utf8 function to support char type in Hive. This function is important, because it also used in ranger-trino plugin for masking.

Additional context and related issues

In hive, create a table using SQL:
CREATE TABLE char_table_test (
id INT,
name string,
description CHAR(120)
);
insert into char_table_test values(1, 'xiaoming', 'he is a student');
insert into char_table_test values(2, 'honghong', 'she is a teacher');

When using function to_utf8 in a sql, there is an error.
To_utf8 doesn't support char type, as below:
SQL1:
select to_utf8(description) from char_table_test;
Query 20231218_125526_00001_ewnva failed: line 1:8: Unexpected parameters (char(120)) for function to_utf8. Expected: to_utf8(varchar(x))
select to_utf8(description) from char_table_test;

SQL2:
select length(from_utf8(to_utf8(description))) from char_table_test;
Query 20231218_125334_00000_ewnva failed: line 1:25: Unexpected parameters (char(120)) for function to_utf8. Expected: to_utf8(varchar(x))
select length(from_utf8(to_utf8(description))) from char_table_test

After changed, it supports char type. As below:

SQL1:
select to_utf8(description) from char_table_test;
_col0

68 65 20 69 73 20 61 20 73 74 75 64 65 6e 74 20+
20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20+
20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20+
20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20+
20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20+
20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20+
20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20+
20 20 20 20 20 20 20 20
73 68 65 20 69 73 20 61 20 74 65 61 63 68 65 72+
20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20+
20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20+
20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20+
20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20+
20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20+
20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20+
20 20 20 20 20 20 20 20
(2 rows)

SQL2:
select from_utf8(to_utf8(description)) from char_table_test;
_col0

she is a teacher
he is a student

SQL3:
select length(from_utf8(to_utf8(description))) from char_table_test;
_col0

120
120
(2 rows)

Release notes

(x) Release notes are required, with the following suggested text:

* Add support for `char(n)` values in {func}`to_utf8`. ({issue}`20158`)

[mosabua]

Docs need update as well

[martint]

Syntax and semantics look good.

[wendigo]

toIntExact(x)

[borderlayout]

OK, I have just updated the code.

[wendigo]

@mosabua please squash these commits into a single one

[mosabua]

@mosabua please squash these commits into a single one

I think @wendigo meant for @borderlayout to squash commits...