[php-src] PR #23762: Fix GH-23756: crash when a collation callback closes the statement cursor

Pull Request: https://github.com/php/php-src/pull/23762 Author: lazerg PDOStatement::closeCursor() calls sqlite3_reset() on the underlying sqlite3_stmt. When a collation callback calls it, the reset lands on the statement sqlite3_step() is still running, SQLite tears down the VDBE under itself, and the process segfaults. Calling execute() again from the same callback crashes the same way, through the reset in the parameter hook and the nested step. The driver statement now records that it is being stepped, and both paths throw an Error instead of reaching SQLite. The running query still finishes, so the statement is usable afterwards. The flag is restored on a bailout too, which keeps closeCursor() working in a shutdown function after a callback called exit(). Fixes #23756