[php-src] Issue #11966: Microtime rate-limited?

Issue: https://github.com/php/php-src/issues/11966 Author: dbuteyn ### Description Some of our automated tests would randomly fail. During these tests, a value seeded with microtime() was being hashed and inserted into a database. Either microtime() doesn't have enough precision or it is being cached somewhere internally because occasionally the test would try to insert a duplicate hash and fail. Considering that microtime() is supposed to have one millionth of a second precision, I can only assume HPET requests are rate-limited in some way, somewhere. Using /dev/urandom instead of microtime() solved the problem for us. To reproduce: Slam Apache server with libapache2-mod-php hard with a large number of concurrent requests that print out microtime(). Eventually, one of the replies will have a duplicate value. ### PHP Version PHP 7.4.33 ### Operating System Debian 11