[php-src] Issue #9916: Entering shutdown sequence with a fiber suspended in a Generator emits an unavoidable fatal error

Issue: https://github.com/php/php-src/issues/9916 Author: bwoebi ### Description The following code: ```php <?php $gen = (function() { try { Fiber::suspend(); yield; } finally { echo "Finally\n"; } })(); $fiber = new Fiber(function() use ($gen, &$fiber) { $gen->current(); }); $fiber->start(); ``` Resulted in this output (_in Unknown on line 0_ is also very helpful to track the issue down...): ``` Fatal error: Cannot resume an already running generator in Unknown on line 0 ``` But I expected this output instead: ``` Finally ``` It seems necessary to add some ordering constraint within the interaction of fibers and generators. (Swapping the creation of the generator and the fiber in this example poses no problems.) ### PHP Version master ### Operating System _No response_