Skip test

After prefixing the trigger_error() call with the error suppression
operator, PHP 7 exits when running this test.

Author: sebastianbergmann

tests/unit/Framework/TestCaseTest.php

@@ -1247,6 +1247,9 @@ public function testWarningCanBeExpected(): void
         trigger_error('foo', E_USER_WARNING);
     }
 
+    /**
+     * @requires PHP 8
+     */
     public function testErrorCanBeExpected(): void
     {
         $this->expectError();