Tests broken by systemd 257.8 -> 257.9

The relevant part of the build log:

tests/test_versions.py::test_version_eq[00-0] PASSED                     [ 99%]
tests/test_versions.py::test_version_eq[000-0] PASSED                    [ 99%]
tests/test_versions.py::test_version_eq[0^-0^] PASSED                    [100%]

=================================== FAILURES ===================================
__________________________________ test_diff ___________________________________

differences = [<Difference ukify inspect {} -- ukify inspect {} []>]

    @skip_unless_tools_exist("objdump")
    @skip_unless_tools_exist("ukify")
    def test_diff(differences):
>       assert_diff(differences[0], "uki_expected_diff")

tests/comparators/test_uki.py:81: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

difference = <Difference ukify inspect {} -- ukify inspect {} []>
filename = 'uki_expected_diff'

    def assert_diff(difference, filename):
        # Assign seen and expected values to local variables to improve contextual
        # information in failed tests.
        seen = difference.unified_diff
        expected = get_data(filename)
>       assert seen == expected
E       AssertionError

tests/utils/data.py:64: AssertionError
---------------------------- Captured stderr setup -----------------------------
/build/pytest-of-nixbld/pytest-0/test_diff2/linux1 is not a valid PE file and cannot be decompressed either
/build/pytest-of-nixbld/pytest-0/test_diff2/linux1 is not a valid PE file, not extracting SBAT section.
.linux in /build/diffoscope-295/tests/data/dummyx64.efi.stub is not a valid PE, ignoring
Wrote unsigned linux1.unsigned.efi
/build/pytest-of-nixbld/pytest-0/test_diff2/linux2 is not a valid PE file and cannot be decompressed either
/build/pytest-of-nixbld/pytest-0/test_diff2/linux2 is not a valid PE file, not extracting SBAT section.
.linux in /build/diffoscope-295/tests/data/dummyx64.efi.stub is not a valid PE, ignoring
Wrote unsigned linux2.unsigned.efi
=========================== short test summary info ============================
FAILED tests/comparators/test_uki.py::test_diff - AssertionError
= 1 failed, 728 passed, 39 skipped, 6 deselected, 1 xfailed, 2 xpassed in 39.52s =

Downstream issue: https://github.com/nixos/nixpkgs/issues/446683