Summary

Fix Modules/_zoneinfo.c:get_local_timestamp() to correctly distinguish a legitimate -1 result from PyLong_AsLong() from an actual conversion error by checking PyErr_Occurred(), matching the documented C API behavior and the pure-Python implementation.

The previous implementation treated any -1 return value from PyLong_AsLong() as an error, even when no exception was set. This caused datetime subclasses overriding hour, minute, or second to return -1 to incorrectly raise an exception in the C accelerator.

This PR also adds a regression test covering datetime subclasses whose hour, minute, and second properties return -1.

Issue

Closes: gh-154892