Delete code that is no longer needed

Author: sebastianbergmann

src/Framework/TestSuite.php

@@ -146,12 +146,6 @@ public function addTest(Test $test, array $groups = []): void
 
         assert($test instanceof TestCase || $test instanceof PhptTestCase);
 
-        $class = new ReflectionClass($test);
-
-        if ($class->isAbstract()) {
-            return;
-        }
-
         $this->tests[] = $test;
 
         $this->clearCaches();