[dunglas]

PHP 8.2.35, 8.3.36, 8.4.27 and 8.5.12 (php/php-src@31c0ea7d7f) replace the bailout on OOM with a delayed fatal error and add a hard memory limit, twice `memory_limit` by default (`memory_hard_limit_percent`). An allocation past it prints "Hard memory limit ... exhausted" and calls `_exit(137)`.

`TestUnhealthyThreadIsRestarted` sent a 16 MiB query string with `memory_limit=8M`: `php_default_treat_data()` copies it in one allocation, which crosses the 16 MiB hard limit and kills the test binary. This is why Tests and Windows are red on main since these releases.

• Replace it with `TestOutOfMemory_module` and `TestOutOfMemory_worker`: a 5 MiB query string (under the hard limit) and an OOM inside the script both end in the usual fatal error and the thread or worker keeps serving. Without the hard limit (detected at runtime), the test still checks that the unhealthy thread is restarted.
• Document in the known issues that crossing the hard limit stops the whole FrankenPHP process, since all requests are served by threads of one process, unlike PHP-FPM which only loses a child.