Fix crash during GC of suspended generator delegate

[arnaud-lb]

We assume that non-running generators have their ->execute_data->opline pointing to the opline next to the yield or yield from that stopped it (e.g. here, here, and here).

However, when fetching the next delegated value for a yield from $nonGenerator, the opline points to the yield from op due to temporary adjustments in zend_generator_get_next_delegated_value().

This causes crashes when cleaning up unfinished calls or assertion failures during GC.

Here I change zend_generator_get_next_delegated_value() to not adjust the opline, so that the expectation is always true.

zend_generator_throw_exception() also adjusts the opline, which causes similar issues if zval_ptr_dtor(&generator->values) triggers the GC. I update it to cancel the adjustment before destroying generator->values.

Alternatively, I think it may be simpler to stop incrementing opline in the yield and yield from op handlers (and to leave this task to zend_generator_resume()), so that we don't have to patch opline in other places. However this targets 8.2, so I didn't explore this idea.

While testing I've also found that calling ->throw() on a running generator, or a child of a running generator, may crash. In [1], the getIterator() generator is getting closed during ->throw(), but its execute_data is accessed after that. In [2] we break zend_generator_throw_exception()'s assumption of being called on a non-running generator. Should we forbid calling ->throw() when zend_generator_get_current() is running?

[dstogov]

This is your code.
You know it better then me.
I don't object.

[bwoebi]

This is sort-of annoying, as the opline now won't point to the line with the yield (from) in stack traces in zend_generator_throw_exception thrown by generator->values destructors (if I understood it correctly?).

I think it would be actually beneficial to not replace the line numbers by %d in these tests.

[arnaud-lb]

This is sort-of annoying, as the opline now won't point to the line with the yield (from) in stack traces in zend_generator_throw_exception thrown by generator->values destructors (if I understood it correctly?).

I think the line number will be correct, luckily, most of the time: YIELD_FROM is probably always followed by an op with the same line number (FREE, ASSIGN, SEND, or other uses of its result).

I think it would be actually beneficial to not replace the line numbers by %d in these tests.

Agreed, I've updated the tests

[bwoebi]

I suppose it's fine then. But yeah, I very much prefer the other patch, which can land only in master though, so please replace it by that one when merging to master.