test: add test for Fore::modifyColumn() and null

Author: kenjis

tests/system/Database/Live/ForgeTest.php

@@ -1285,11 +1285,6 @@ public function testModifyColumnRename()
 
     public function testModifyColumnNullTrue()
     {
-        // @TODO remove this in `4.4` branch
-        if ($this->db->DBDriver === 'SQLSRV') {
-            $this->markTestSkipped('SQLSRV does not support getFieldData() nullable.');
-        }
-
         $this->forge->dropTable('forge_test_modify', true);
 
         $this->forge->addField([
@@ -1319,11 +1314,6 @@ public function testModifyColumnNullTrue()
 
     public function testModifyColumnNullFalse()
     {
-        // @TODO remove this in `4.4` branch
-        if ($this->db->DBDriver === 'SQLSRV') {
-            $this->markTestSkipped('SQLSRV does not support getFieldData() nullable.');
-        }
-
         $this->forge->dropTable('forge_test_modify', true);
 
         $this->forge->addField([