Add tests for setting and deleting attributes defined in C

CPython defines 375 attributes with PyMemberDef and PyGetSetDef (excluding the _test* modules), but the test suite never assigns to 187 of them and never deletes 332 of them.

Deletion in particular is almost untested, although it is a separate code path: the setter is called with NULL, and an implementation which does not expect this crashes or leaves the object in a broken state.

Three bugs found this way are gh-156099, gh-156100 and gh-156101; gh-152817 is another one.

The following PR adds writing and deleting tests for each writable attribute.

Linked PRs

• gh-156107
• gh-156184
• gh-156191

首先找出 CPython 中針對使用 PyMemberDef 和 PyGetSetDef 定義之屬性的測試涵蓋範圍。檢視目前如何指派及刪除可寫入屬性，然後利用已回報的缺口和現有測試涵蓋每個可寫入屬性。完成的標準是：所有可寫入屬性的指派和刪除都經過測試，且不會發生崩潰或物件損壞。