HashTableIterators of empty hashtables are not poisoned upon destruction

Description

Using the zend_hash_iterators_* API, non-empty arrays are properly marked as poisoned in the HashTableIterator entries when destroyed.

However there is an edge case: if nNumUsed == 0 (thanks to deletion of entries during iteration), then the zend_hash_iterators_remove call is skipped in zend_hash_destroy.

Thus, we either should:
a) fix this by always calling the removal ... or
b) completely remove the auto-removal on destruction and leave it the extension authors responsibility to clear the iterators (making zend_hash_iterators_remove public API)

From the perspective of the code in php-src there is no need to have the auto-removal on free, as every iterating thing holds a reference to it.

PHP Version

master

Operating System

No response

检查 zend_hash_destroy 路径以及 zend_hash_iterators_remove，重点关注迭代期间删除后 nNumUsed == 0 的情况。确定 API 应保证哪种迭代器清理行为，然后验证空和非空 hashtable 是否留下预期的 poisoned 状态。