Remove deprecated code paths

Author: nicolas-grekas

HttpClient/Test/HttpClientTestCase.php

@@ -1074,10 +1074,6 @@ public function testMaxDuration()
     public function testWithOptions()
     {
         $client = $this->getHttpClient(__FUNCTION__);
-        if (!method_exists($client, 'withOptions')) {
-            $this->markTestSkipped(sprintf('Not implementing "%s::withOptions()" is deprecated.', get_debug_type($client)));
-        }
-
         $client2 = $client->withOptions(['base_uri' => 'http://localhost:8057/']);
 
         $this->assertNotSame($client, $client2);