Fix the detection of HTML5 support in the testsuite

The detection relied on detecting the test method added when introducing
the feature in symfony/dom-crawler. But as of Symfony 4.4, tests are
stripped from the dist archives. An additional detection based on a new
method added in later Symfony version is now used to filter out the
false positives (not detecting 4.4 and newer as being <3.3).

tests/BrowserKitConfig.php

@@ -45,6 +45,8 @@ public function skipMessage($testCase, $test)
                 'testHtml5FormMethod',
             ))
             && !method_exists('Symfony\Component\DomCrawler\Tests\FormTest', 'testGetMethodWithOverride')
+            // Symfony 4.4 removed tests from dist archives, making the previous detection return a false-positive
+            && !method_exists('Symfony\Component\DomCrawler\Form', 'getName')
         ) {
             return 'Mink BrowserKit doesn\'t support HTML5 form attributes before Symfony 3.3';
         }