feat: adds regex_extract function and more type tests (#7107)

* feat: adds format, regex_extract function and more type tests

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

* fix: forgot functions

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

* chore: forgot null type

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

* test: forgot date type

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

* feat: remove format function

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

* test: update results after upgrading datafusion

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

---------

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

tests/cases/standalone/common/function/string/repeat.sql

@@ -0,0 +1,68 @@
+-- String REPEAT function tests
+
+-- Basic REPEAT function
+SELECT REPEAT('hello', 3);
+
+SELECT REPEAT('a', 5);
+
+SELECT REPEAT('', 3);
+
+SELECT REPEAT('test', 0);
+
+SELECT REPEAT('test', 1);
+
+-- REPEAT with NULL values
+SELECT REPEAT(NULL, 3);
+
+SELECT REPEAT('hello', NULL);
+
+-- REPEAT with negative numbers
+SELECT REPEAT('hello', -1);
+
+-- REPEAT with special characters
+SELECT REPEAT('*', 10);
+
+SELECT REPEAT('-=', 5);
+
+SELECT REPEAT('!@#', 3);
+
+-- Test with table data
+CREATE TABLE repeat_test(s VARCHAR, n INTEGER, ts TIMESTAMP TIME INDEX);
+
+INSERT INTO repeat_test VALUES
+    ('hello', 2, 1000),
+    ('*', 5, 2000),
+    ('test', 0, 3000),
+    ('a', 10, 4000),
+    (NULL, 3, 5000),
+    ('hi', NULL, 6000);
+
+SELECT s, n, REPEAT(s, n) FROM repeat_test ORDER BY ts;
+
+-- Unicode REPEAT
+SELECT REPEAT('世', 3);
+
+SELECT REPEAT('🚀', 5);
+
+SELECT REPEAT('café', 2);
+
+-- REPEAT with spaces and formatting
+SELECT REPEAT(' ', 10);
+
+SELECT REPEAT('\t', 3);
+
+SELECT CONCAT('Start', REPEAT('-', 10), 'End');
+
+-- Large REPEAT operations
+SELECT LENGTH(REPEAT('a', 100));
+
+SELECT LENGTH(REPEAT('ab', 50));
+
+-- Combining REPEAT with other functions
+SELECT UPPER(REPEAT('hello', 3));
+
+SELECT REPEAT(UPPER('hello'), 2);
+
+SELECT REVERSE(REPEAT('abc', 3));
+
+DROP TABLE repeat_test;