Need to keep traceback alive in WITH_EXCEPT_START

Bug report

Bug description:

Currently in WITH_EXCEPT_START the interpreter loop gets the traceback from the exception object and then immediately decref's it before calling the __exit__ function. But the __exit__ function may not incref the traceback (if it's not an interpretedPython function) and could cause the traceback to be replaced on the exception, leading it holding onto a freed traceback.

CPython versions tested on:

CPython main branch, 3.12

Operating systems tested on:

Linux

Linked PRs

• gh-130562
• gh-130626

先查看關聯的 PR gh-130562 和 gh-130626，然後定位 CPython 中直譯器迴圈的 WITH_EXCEPT_START 實作。驗證在 exit 執行期間 traceback 仍然有效，並為回報的替換和生命週期情境新增或更新涵蓋測試。