minor #25908 Improve assertions (carusogabriel)

This PR was merged into the 2.8 branch.

Discussion
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Improve assertions

| Q             | A
| ------------- | ---
| Branch?       | 2.8
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Following #25420 in `2.8` branch.

Commits
-------

4683f6d454 Improve assertions

Author: fabpot

Tests/Compiler/ResolveDefinitionTemplatesPassTest.php

@@ -280,23 +280,23 @@ public function testDeepDefinitionsResolving()
         $this->process($container);
 
         $configurator = $container->getDefinition('sibling')->getConfigurator();
-        $this->assertSame('Symfony\Component\DependencyInjection\Definition', get_class($configurator));
+        $this->assertInstanceOf('Symfony\Component\DependencyInjection\Definition', $configurator);
         $this->assertSame('parentClass', $configurator->getClass());
 
         $factory = $container->getDefinition('sibling')->getFactory();
-        $this->assertSame('Symfony\Component\DependencyInjection\Definition', get_class($factory[0]));
+        $this->assertInstanceOf('Symfony\Component\DependencyInjection\Definition', $factory[0]);
         $this->assertSame('parentClass', $factory[0]->getClass());
 
         $argument = $container->getDefinition('sibling')->getArgument(0);
-        $this->assertSame('Symfony\Component\DependencyInjection\Definition', get_class($argument));
+        $this->assertInstanceOf('Symfony\Component\DependencyInjection\Definition', $argument);
         $this->assertSame('parentClass', $argument->getClass());
 
         $properties = $container->getDefinition('sibling')->getProperties();
-        $this->assertSame('Symfony\Component\DependencyInjection\Definition', get_class($properties['prop']));
+        $this->assertInstanceOf('Symfony\Component\DependencyInjection\Definition', $properties['prop']);
         $this->assertSame('parentClass', $properties['prop']->getClass());
 
         $methodCalls = $container->getDefinition('sibling')->getMethodCalls();
-        $this->assertSame('Symfony\Component\DependencyInjection\Definition', get_class($methodCalls[0][1][0]));
+        $this->assertInstanceOf('Symfony\Component\DependencyInjection\Definition', $methodCalls[0][1][0]);
         $this->assertSame('parentClass', $methodCalls[0][1][0]->getClass());
     }