CIFuzz fails on the 3.13 and 3.14 branches: plistlib parse and LookupError

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Bug report

Examples on a 3.13 PR:

• CIFuzz / python3-libraries (address): https://github.com/python/cpython/actions/runs/28177183993/job/83456696673#logs
• CIFuzz / cpython3 (undefined): https://github.com/python/cpython/actions/runs/28177183993/job/83456696702#logs
• CIFuzz / cpython3 (memory): https://github.com/python/cpython/actions/runs/28177183993/job/83456696797

Example on the address job:

Traceback (most recent call last):
  File "<string>", line 7, in FuzzerRunOne
  File "/github/workspace/build-out/cpython-install/lib/python3.13/plistlib.py", line 925, in loads
    return load(fp, fmt=fmt, dict_type=dict_type, aware_datetime=aware_datetime)
  File "/github/workspace/build-out/cpython-install/lib/python3.13/plistlib.py", line 912, in load
    return p.parse(fp)
           ~~~~~~~^^^^
  File "/github/workspace/build-out/cpython-install/lib/python3.13/plistlib.py", line 194, in parse
    self.parser.ParseFile(fileobj)
    ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
LookupError: unknown encoding: Latin-5_________________________

The artifacts ZIP contains:

<?xml version="2147483646.256" encoding="Latin-5_________________________"  ?><svg><svg><svg

cc @StanFromIreland @serhiy-storchaka