Facing test issues on PPC64LE architecture.

While executing tests for the version:v5.9.2 facing test issues,community need to update the source code:

`================================================================== test session starts ==================================================================
platform linux -- Python 3.11.2, pytest-7.4.3, pluggy-1.3.0
rootdir: /nbformat
configfile: pyproject.toml
testpaths: tests/
plugins: anyio-4.0.0
collected 189 items

tests/test_api.py ...... [ 3%]
tests/test_convert.py ..... [ 5%]
tests/test_nbformat.py ..... [ 8%]
tests/test_reader.py ... [ 10%]
tests/test_sign.py ................... [ 20%]
tests/test_validator.py ..XX.............................................. [ 46%]
tests/v1/test_json.py . [ 47%]
tests/v1/test_nbbase.py ...... [ 50%]
tests/v2/test_json.py ... [ 51%]
tests/v2/test_nbbase.py ............. [ 58%]
tests/v2/test_nbpy.py . [ 59%]
tests/v3/test_json.py ........... [ 65%]
tests/v3/test_misc.py . [ 65%]
tests/v3/test_nbbase.py ...................... [ 77%]
tests/v3/test_nbpy.py ..... [ 79%]
tests/v4/test_convert.py ...... [ 83%]
tests/v4/test_json.py ............. [ 89%]
tests/v4/test_nbbase.py .............. [ 97%]
tests/v4/test_validate.py ..... [100%]

=================================================================== warnings summary ====================================================================
../usr/local/lib/python3.11/site-packages/jupyter_core/application.py:22
/usr/local/lib/python3.11/site-packages/jupyter_core/application.py:22: DeprecationWarning: Jupyter is migrating its paths to use standard platformdirs
given by the platformdirs library. To remove this warning and
see the appropriate new directories, set the environment variable
`JUPYTER_PLATFORM_DIRS=1` and then run `jupyter --paths`.
The use of platformdirs will be the default in `jupyter_core` v6
from .paths import (

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
================================================================= slowest 10 durations ==================================================================
0.76s call tests/test_sign.py::TestNotary::test_sign_stdin
0.12s call tests/test_sign.py::TestNotary::test_invalid_db_file
0.11s call tests/test_validator.py::test_nb2[jsonschema]
0.09s call tests/test_validator.py::test_future[fastjsonschema]
0.06s call tests/test_validator.py::test_invalid_validator_raises_value_error_after_read
0.06s call tests/test_validator.py::test_future[jsonschema]
0.06s call tests/test_api.py::TestAPI::test_read
0.05s call tests/test_validator.py::test_nb3[jsonschema]
0.05s call tests/test_api.py::TestAPI::test_capture_validation_error
0.05s call tests/test_validator.py::test_nb4jupyter_metadata_timings[fastjsonschema]
================================================================ short test summary info ================================================================
XPASS tests/test_validator.py::test_should_not_mutate[fastjsonschema] In the future we want to stop warning, and raise an error
XPASS tests/test_validator.py::test_should_not_mutate[jsonschema] In the future we want to stop warning, and raise an error
======================================================= 187 passed, 2 xpassed, 1 warning in 2.81s =======================================================`
```[tasklist]
### Tasks
```

The report identifies a Python 3.11 pytest run under tests/ on PPC64LE, but names no failing test or source file. First reproduce the v5.9.2 test run on PPC64LE and isolate the actual failure. Done means the affected tests pass on that architecture and the required source change is covered by a regression test.

Written by the indexing model from the issue text.