Issue #2210631 by damiankloip: Move PhpStorageFactory to the Core namespace.

core/includes/common.inc

core/includes/utility.inc

core/lib/Drupal/Core/DrupalKernel.php

core/lib/Drupal/Core/PhpStorage/PhpStorageFactory.php

core/lib/Drupal/Core/Template/TwigEnvironment.php

core/modules/language/language.module

...guage/lib/Drupal/language/ConfigurableLanguageManager.php

.../lib/Drupal/language/EventSubscriber/ConfigSubscriber.php

...es/system/lib/Drupal/system/PhpStorage/MockPhpStorage.php

.../Drupal/system/Tests/PhpStorage/PhpStorageFactoryTest.php

...system/lib/Drupal/system/Tests/Theme/TwigSettingsTest.php

...sts/Drupal/Tests/Component/PhpStorage/FileStorageTest.php

...ts/Component/PhpStorage/MTimeProtectedFileStorageBase.php

.../Drupal/Tests/Component/PhpStorage/PhpStorageTestBase.php

core/tests/Drupal/Tests/Component/Plugin/PluginBaseTest.php