Some C code in the interpreter and standard library still performs reference-counting operations on objects already known to be Py_None.

None has been immortal since Python 3.12. These operations do not change its reference count, but may still generate runtime checks. Similar cleanup was accepted in #103922, as part of #103906.

I propose extending that cleanup in a small series of focused PRs:

• Remove explicit reference-counting operations on Py_None.
• Remove operations on variables already checked to be Py_None.
• Separately review call sites whose internal helper always returns None on success.

Compatibility with Limited API versions before 3.12 and tests specifically exercising reference-counting APIs would be preserved. Other immortal objects are outside the scope.

No Python-level behavior changes are intended.