Issue #1999430 by chertzog, andypost, slv_, kim.pepper: Use Symfony Request for simpletest module.

core/modules/simpletest/lib/Drupal/simpletest/UnitTestBase.php

@@ -67,9 +67,6 @@ protected function setUp() {
       return FALSE;
     }
 
-    // Set user agent to be consistent with WebTestBase.
-    $_SERVER['HTTP_USER_AGENT'] = $this->databasePrefix;
-
     $this->setup = TRUE;
   }
 }