Database file handles are not released on `restart`

[Maxxen]

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 "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "D:\a\duckdb-inet\duckdb-inet\configure\venv\Lib\site-packages\duckdb_sqllogictest\__main__.py", line 3, in <module>
    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.