For PyPy only, re-enable old behavior (runs the risk of masking bugs) (#4079)
* For PyPy only, re-enable old behavior (likely to mask bugs), to avoid segfault with unknown root cause.
Change prompted by https://github.com/pybind/pybind11/issues/4075
* Undo the change in tests/test_exceptions.py
I turns out (I forgot) that PyPy segfaults in `test_flaky_exception_failure_point_init` already before the `MISMATCH` code path is reached:
https://github.com/pybind/pybind11/runs/7383663596
```
RPython traceback:
test_exceptions.py .......X.........Error in cpyext, CPython compatibility layer:
File "pypy_module_cpyext.c", line 14052, in wrapper_second_level__star_3_1
File "pypy_module_cpyext_1.c", line 35750, in not_supposed_to_fail
Fatal Python error: Segmentation fault
Stack (most recent call first, approximate line numbers):
File "/home/runner/work/pybind11/pybind11/tests/test_exceptions.py", line 306 in test_flaky_exception_failure_point_init
The function PyErr_NormalizeException was not supposed to fail
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/python.py", line 185 in pytest_pyfunc_call
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_callers.py", line 9 in _multicall
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_manager.py", line 77 in _hookexec
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_hooks.py", line 244 in __call__
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/python.py", line 1716 in runtest
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/runner.py", line 159 in pytest_runtest_call
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_callers.py", line 9 in _multicall
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_manager.py", line 77 in _hookexec
Fatal error in cpyext, CPython compatibility layer, calling PyErr_NormalizeException
Either report a bug or consider not using this particular extension
<SystemError object at 0x7fcc8cea6868>
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_hooks.py", line 244 in __call__
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/runner.py", line 261 in <lambda>
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/runner.py", line 317 in from_call
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/runner.py", line 246 in call_runtest_hook
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/runner.py", line 218 in call_and_report
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/runner.py", line 118 in runtestprotocol
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/runner.py", line 110 in pytest_runtest_protocol
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_callers.py", line 9 in _multicall
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_manager.py", line 77 in _hookexec
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_hooks.py", line 244 in __call__
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/main.py", line 335 in pytest_runtestloop
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_callers.py", line 9 in _multicall
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_manager.py", line 77 in _hookexec
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_hooks.py", line 244 in __call__
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/main.py", line 318 in _main
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/main.py", line 255 in wrap_session
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/main.py", line 314 in pytest_cmdline_main
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_callers.py", line 9 in _multicall
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_manager.py", line 77 in _hookexec
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pluggy/_hooks.py", line 244 in __call__
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/config/__init__.py", line 133 in main
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/_pytest/config/__init__.py", line 181 in console_main
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/site-packages/pytest/__main__.py", line 1 in <module>
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/lib-python/3/runpy.py", line 62 in _run_code
File "/opt/hostedtoolcache/PyPy/3.7.13/x64/lib-python/3/runpy.py", line 170 in _run_module_as_main
File "<builtin>/app_main.py", line 109 in run_toplevel
File "<builtin>/app_main.py", line 652 in run_command_line
File "<builtin>/app_main.py", line 996 in entry_point
Segmentation fault (core dumped)
```
* Add test_pypy_oserror_normalization
* Disable new `PYPY_VERSION` `#if`, to verify that the new test actually fails.
* Restore PYPY_VERSION workaround and update comment to reflect what was learned.
* [ci skip] Fix trivial oversight in comment.
3 files changed
