Description:
------------
When I use sleep() method in my script and set `process_control_timeout` to `20s` in php-fpm.conf, I see unexpected behavior when I reload the php-fpm. It seems it doesn't respect the sleep's argument (e.g. 10 seconds) and wakes up the script too early. 

However, when I use `exec('sleep 10')` instead, it works correctly:


```
[02-11-2019 11:39:15] before sleep
[02-11-2019 11:39:25] after sleep
[02-11-2019 11:39:25] after echo
```


PHP Version: PHP 7.3.2-3+ubuntu18.04.1+deb.sury.org+1 (cli) (built: Feb  8 2019 15:43:57) ( NTS )
Webserver: Nginx - using unix socket

Test script:
---------------
<?php

slog("before sleep");

// this works:
// exec('sleep 10');

// but, this doesn't work:
sleep(10);

slog("after sleep");

echo "Done!" . PHP_EOL;
slog("after echo");


function slog(string $text) {
    $text = '[' . strftime("%m-%d-%Y %H:%M:%S") . '] ' . $text . PHP_EOL;
    file_put_contents(__DIR__ . '/app.log', $text, FILE_APPEND);
}

Expected result:
----------------
[02-11-2019 11:38:43] before sleep
[02-11-2019 11:38:53] after sleep
[02-11-2019 11:38:53] after echo

Actual result:
--------------
[02-11-2019 11:38:43] before sleep
[02-11-2019 11:38:46] after sleep
[02-11-2019 11:38:46] after echo