`zend_extension` php.ini uses different path discovery than `extension`

Description

Steps to reproduce:

File structure:

• ./ - current directory
• ./php-8.1.12-nts-Win32-vs16-x64 - extracted from official Windows download
• ./php-8.1.12-nts-Win32-vs16-x64\ext\php_xdebug.dll - downloaded from official xdebug website

When I run .\php-8.1.12-nts-Win32-vs16-x64\php.exe -d xdebug.mode=coverage -d extension=ext/php_xdebug test.php I get:

Warning: Xdebug MUST be loaded as a Zend extension in Unknown on line 0
... (xdebug is working, output from test.php code)

When I run .\php-8.1.12-nts-Win32-vs16-x64\php.exe -d xdebug.mode=coverage -d zend_extension=ext/php_xdebug.dll test.php I get:

Warning: Failed loading Zend extension 'ext/php_xdebug.dll' (tried: C:\php\ext\ext/php_xdebug.dll (The specified module could not be found), C:\php\ext\php_ext/php_xdebug.dll.dll (The specified module could not be found)) in Unknown on line 0

Fatal error: Uncaught Error: Call to undefined function xdebug_start_code_coverage() in C:\Users\mvorisek\Desktop\forks\cov-php81-debug\test.php:5
Stack trace:
#0 {main}
  thrown in C:\Users\mvorisek\Desktop\forks\cov-php81-debug\test.php on line 5

I would expect exactly the same extension discovery for extension and zend_extension.

(and I can confirm zend_extension with absolute php_xdebug.dll path is working)

PHP Version

PHP 8.1.12 NTS Win x64

Operating System

Windows 10

Empieza reproduciendo las dos líneas de comandos de Windows contra la compilación PHP 8.1.12 NTS y compara el manejo de rutas relativas para extension y zend_extension. Rastrea los puntos de entrada de carga de extensiones y su comportamiento de resolución de rutas; se considera terminado cuando ambas directivas encuentran la misma ruta relativa de DLL sin cambiar el comportamiento para rutas absolutas.