Merge branch '3.4' into 4.3

* 3.4:
  Remove use of ForwardCompatTrait
  Remove deprecated methods assertArraySubset

Author: nicolas-grekas

Tests/HttpHeaderSerializerTest.php

@@ -13,19 +13,16 @@
 
 use Fig\Link\Link;
 use PHPUnit\Framework\TestCase;
-use Symfony\Bridge\PhpUnit\ForwardCompatTestTrait;
 use Symfony\Component\WebLink\HttpHeaderSerializer;
 
 class HttpHeaderSerializerTest extends TestCase
 {
-    use ForwardCompatTestTrait;
-
     /**
      * @var HttpHeaderSerializer
      */
     private $serializer;
 
-    private function doSetUp()
+    protected function setUp()
     {
         $this->serializer = new HttpHeaderSerializer();
     }