normalize_url test failures with Python 3.12

[ckastner]

Hi,

with Python 3.12, I'm seeing the following test failures:

======================================================================
FAIL: test_normalize_url_slashes (tests.test_locations.TestLocations.test_normalize_url_slashes)
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Traceback (most recent call last):
  File "/python-xmlschema-3.3.1/tests/test_locations.py", line 314, in test_normalize_url_slashes
    self.assertRegex(normalize_url('////root/dir1/schema.xsd'),
AssertionError: Regex didn't match: 'file:////root/dir1/schema.xsd' not found in 'file://////root/dir1/schema.xsd'

======================================================================
FAIL: test_normalize_url_with_base_unc_path (tests.test_locations.TestLocations.test_normalize_url_with_base_unc_path)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/python-xmlschema-3.3.1/tests/test_locations.py", line 283, in test_normalize_url_with_base_unc_path
    self.assertEqual(url, 'file:////filer01/MY_HOME/dev/XMLSCHEMA/test.xsd')
AssertionError: 'file://///filer01/MY_HOME/dev/XMLSCHEMA/test.xsd' != 'file:////filer01/MY_HOME/dev/XMLSCHEMA/test.xsd'
- file://///filer01/MY_HOME/dev/XMLSCHEMA/test.xsd
?      -
+ file:////filer01/MY_HOME/dev/XMLSCHEMA/test.xsd

Looking at the changelog of 3.12, there were a few changes to urllib, though it's not immediately obvious to me which one could have affected this (or if these change even were the cause).