[php-src] Issue #20973: How to throw an exception in a custom opcode handler?

Issue: https://github.com/php/php-src/issues/20973
Author: matyhtf

### Description

Code: https://github.com/swoole/phpy/blob/main/src/php/operator.cc#L319

In the phpy extension, we use opcode handlers to implement operator overloading for Python objects. However, when an exception is thrown in the opcode handler function, it causes a crash.

My question is how to safely throw an exception in a custom opcode handler?

```c
#define ZEND_USER_OPCODE_CONTINUE   0 /* execute next opcode */
#define ZEND_USER_OPCODE_RETURN     1 /* exit from executor (return from function) */
#define ZEND_USER_OPCODE_DISPATCH   2 /* call original opcode handler */
#define ZEND_USER_OPCODE_ENTER      3 /* enter into new op_array without recursion */
#define ZEND_USER_OPCODE_LEAVE      4 /* return to calling op_array within the same executor */
```

Which value should be returned?

There is no documentation or example code to refer to, so I can only submit an issue.