allow to skip tests based on the supported version

Writing tests for Form related features in the Doctrine and Twig bridges
as well as the FrameworkBundle is a pain as soon as these tests are run
with more recent versions of the Form component. This is due to the fact
that our tests in the bridges and bundle extend test cases from the
component. The tests in the component are expanded with every feature
that gets added there. However, these new features are not present in
the other packages in older version and we thus need to be able to skip
them somehow.

Author: xabbuh

Tests/Form/Type/EntityTypePerformanceTest.php

@@ -30,6 +30,8 @@ class EntityTypePerformanceTest extends FormPerformanceTestCase
      */
     private $em;
 
+    protected static $supportedFeatureSetVersion = 304;
+
     protected function getExtensions()
     {
         $manager = $this->getMockBuilder('Doctrine\Common\Persistence\ManagerRegistry')->getMock();

Tests/Form/Type/EntityTypeTest.php

@@ -57,6 +57,8 @@ class EntityTypeTest extends BaseTypeTest
      */
     private $emRegistry;
 
+    protected static $supportedFeatureSetVersion = 304;
+
     protected function setUp()
     {
         $this->em = DoctrineTestHelper::createTestEntityManager();