Skip some stubgen tests on Windows (#7964)

It appears they do not work.

Author: emmatyping

mypy/test/teststubgen.py

@@ -31,6 +31,7 @@
 class StubgenCmdLineSuite(unittest.TestCase):
     """Test cases for processing command-line options and finding files."""
 
+    @unittest.skipIf(sys.platform == 'win32', "clean up fails on Windows")
     def test_files_found(self) -> None:
         current = os.getcwd()
         with tempfile.TemporaryDirectory() as tmp:
@@ -51,6 +52,7 @@ def test_files_found(self) -> None:
             finally:
                 os.chdir(current)
 
+    @unittest.skipIf(sys.platform == 'win32', "clean up fails on Windows")
     def test_packages_found(self) -> None:
         current = os.getcwd()
         with tempfile.TemporaryDirectory() as tmp: