test: remove database.db after testing

Author: kenjis

tests/system/Database/Live/SQLite3/GetFieldDataTest.php

@@ -147,5 +147,7 @@ public function testGetFieldData(): void
             ]),
             json_encode($fields)
         );
+
+        $this->forge->dropDatabase(WRITEPATH . 'database.db');
     }
 }

tests/system/Database/Live/SQLite3/GetIndexDataTest.php

@@ -45,7 +45,6 @@ protected function setUp(): void
             'database' => 'database.db',
             'DBDebug'  => true,
         ];
-
         $this->db    = db_connect($config);
         $this->forge = Database::forge($config);
     }
@@ -100,5 +99,7 @@ public function testGetIndexData(): void
         $this->assertSame($expectedIndexes['testuser_country']->type, $indexes['testuser_country']->type);
 
         $this->forge->dropTable('testuser', true);
+
+        $this->forge->dropDatabase(WRITEPATH . 'database.db');
     }
 }