[Windows] Fix some unit tests (#6865)

This PR is a part of the effort to remove the last broken unit tests in certbot codebase for Windows, as described in #6850.

This PR fixes various unit tests on Windows, whose resolution was only to modify some logic in the tests, or minor changes in certbot codecase impacting Windows only (like handling correctly paths with DOS-style).

* Correct several tests

* Skip test definitively

* Test to be reactivated with #6497

* Mock log system to avoid errors due to multiple calls to main in main_test

* Simplify mock

* Update cli_test.py

* One test to be repaired when windows file permissions PR is merged

certbot/plugins/manual_test.py

@@ -106,10 +106,10 @@ class AuthenticatorTest(test_util.TempDirTestCase):
                 achall.validation(achall.account_key) in args[0])
             self.assertFalse(kwargs['wrap'])
 
-    @test_util.broken_on_windows
     def test_cleanup(self):
         self.config.manual_public_ip_logging_ok = True
-        self.config.manual_auth_hook = 'echo foo;'
+        self.config.manual_auth_hook = ('{0} -c "import sys; sys.stdout.write(\'foo\')"'
+                                        .format(sys.executable))
         self.config.manual_cleanup_hook = '# cleanup'
         self.auth.perform(self.achalls)