Database file handles are not released on `restart`

Basically, on windows CI runners the filesystem is very slow, and when running a lot of fast tests we get a locking error on the database file handle. Found here https://github.com/Maxxen/duckdb-inet/actions/runs/17855995577/job/50776045739

```
Traceback (most recent call last):
File "", line 198, in _run_module_as_main
File "", line 88, in _run_code
File "D:\a\duckdb-inet\duckdb-inet\configure\venv\Lib\site-packages\duckdb_sqllogictest\__main__.py", line 3, in
SQLLogicPythonRunner().run()
File "D:\a\duckdb-inet\duckdb-inet\configure\venv\Lib\site-packages\duckdb_sqllogictest\python_runner.py", line 208, in run
result = executor.execute_test(test)
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "D:\a\duckdb-inet\duckdb-inet\configure\venv\Lib\site-packages\duckdb_sqllogictest\python_runner.py", line 129, in execute_test
os.remove(loaded_path)
PermissionError: [WinError 32] The process cannot access the file because it is being used by another process: 'test/sql/store_ipv6_inet.db'
[1/12] test\sql\inet\test_inet_escape.test
```

We should make sure to explicitly close/drop the database file handle when restarting, and not wait for python GC to free the resource.