[HttpKernel] Add $kernel->getBuildDir() to separate it from the cache directory

Author: mnapoli

Tests/DependencyInjection/Compiler/AddSessionDomainConstraintPassTest.php

@@ -125,6 +125,7 @@ private function createContainer($sessionStorageOptions)
         $container = new ContainerBuilder();
         $container->setParameter('kernel.bundles_metadata', []);
         $container->setParameter('kernel.cache_dir', __DIR__);
+        $container->setParameter('kernel.build_dir', __DIR__);
         $container->setParameter('kernel.charset', 'UTF-8');
         $container->setParameter('kernel.container_class', 'cc');
         $container->setParameter('kernel.debug', true);