minor #54785 Remove calls to TestCase::iniSet() and calls to deprecated methods of MockBuilder (alexandre-daubois)

This PR was merged into the 5.4 branch.

Discussion
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Remove calls to `TestCase::iniSet()` and calls to deprecated methods of `MockBuilder`

| Q             | A
| ------------- | ---
| Branch?       | 5.4
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Issues        | -
| License       | MIT

Last round (before new deprecations 🙂). All deprecations [listed here](https://github.com/sebastianbergmann/phpunit/blob/main/DEPRECATIONS.md) should be gone.

Commits
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4d5065ddd9 Remove calls to `TestCase::iniSet()` and calls to deprecated methods of `MockBuilder`

Author: xabbuh

Tests/Loader/ObjectLoaderTest.php

@@ -81,9 +81,8 @@ public function testExceptionOnBadMethod()
     public function testExceptionOnMethodNotReturningCollection()
     {
         $this->expectException(\LogicException::class);
-        $service = $this->getMockBuilder(\stdClass::class)
-            ->addMethods(['loadRoutes'])
-            ->getMock();
+
+        $service = $this->createMock(CustomRouteLoader::class);
         $service->expects($this->once())
             ->method('loadRoutes')
             ->willReturn('NOT_A_COLLECTION');
@@ -109,6 +108,11 @@ protected function getObject(string $id): object
     }
 }
 
+interface CustomRouteLoader
+{
+    public function loadRoutes();
+}
+
 class TestObjectLoaderRouteService
 {
     private $collection;