Build/Test Tools: Remove the copied-in PHPUnit 9.x MockObject files.

As the version constraints for PHPUnit now allow the tests to be run on PHPUnit 8.x and 9.x, these files are no longer needed.

Follow-up to [48957], [49037], [51544], [51559-51574].

Props jrf.
See #46149.

git-svn-id: https://develop.svn.wordpress.org/trunk@51575 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

phpcs.xml.dist

@@ -134,8 +134,6 @@
 	<exclude-pattern>/src/wp-includes/sodium_compat/*</exclude-pattern>
 	<exclude-pattern>/src/wp-includes/Text/*</exclude-pattern>
 
-	<exclude-pattern>/tests/phpunit/includes/phpunit7/MockObject/*</exclude-pattern>
-
 	<!-- Test data and fixtures. -->
 	<exclude-pattern>/tests/phpunit/build*</exclude-pattern>
 	<exclude-pattern>/tests/phpunit/data/*</exclude-pattern>

tests/phpunit/includes/bootstrap.php

@@ -46,10 +46,6 @@
 	exit( 1 );
 }
 
-// Register a custom autoloader for the PHPUnit 9.x Mockobject classes for compatibility with PHP 8.0.
-require_once __DIR__ . '/class-mockobject-autoload.php';
-spl_autoload_register( 'MockObject_Autoload::load', true, true );
-
 // Check that the PHPUnit Polyfills autoloader exists.
 $phpunit_polyfills_autoloader = __DIR__ . '/../../../vendor/yoast/phpunit-polyfills/phpunitpolyfills-autoload.php';
 if ( ! file_exists( $phpunit_polyfills_autoloader ) ) {