test: fsinfo: set u+rwx on directories on teardown

We have a fixture which creates a bunch of testcases for unit testing
fsinfo, including cases where we don't have access to access
directories.  This prevents pytest's tmpdir pruning from cleaning up
after the test.

Make sure we set mode 0777 on all directories after we're done.

This takes care of the pile of warnings like

      warnings.warn(
    /usr/lib/python3.12/site-packages/_pytest/pathlib.py:95: PytestWarning: (rm_rf) error removing /tmp/pytest-of-lis/garbage-1fa620ed-1fff-4854-aa93-d6a13d1567e3
    <class 'OSError'>: [Errno 39] Directory not empty: '/tmp/pytest-of-lis/garbage-1fa620ed-1fff-4854-aa93-d6a13d1567e3'
that you otherwise get after a few runs of the test (once pytest start
trying to prune the tmpdir of the older runs).

test/pytest/test_bridge.py

@@ -14,7 +14,7 @@
 import unittest.mock
 from collections import deque
 from pathlib import Path
-from typing import Dict, Iterable, Sequence
+from typing import Dict, Iterable, Iterator, Sequence
 
 import pytest
 
@@ -1010,7 +1010,7 @@ def fsinfo_err(err: int) -> JsonObject:
 
 
 @pytest.fixture
-def fsinfo_test_cases(tmp_path: Path) -> 'dict[Path, JsonObject]':
+def fsinfo_test_cases(tmp_path: Path) -> 'Iterator[dict[Path, JsonObject]]':
     # a normal directory
     normal_dir = tmp_path / 'dir'
     normal_dir.mkdir()
@@ -1081,7 +1081,15 @@ def fsinfo_test_cases(tmp_path: Path) -> 'dict[Path, JsonObject]':
         del expected_state[no_r_dir]
         del expected_state[no_r_file]
 
-    return expected_state
+    try:
+        yield expected_state
+
+    finally:
+        # restore writable permissions on directories.  pytest has trouble cleaning
+        # these up, otherwise...
+        for path in expected_state:
+            if not path.is_symlink() and path.is_dir():
+                path.chmod(0o700)
 
 
 @pytest.mark.asyncio