Issue #1564832 by sun, dcam: Remove _node_extract_type() and node_type_get_name().

core/modules/forum/forum.module

core/modules/node/lib/Drupal/node/NodeFormController.php

core/modules/node/lib/Drupal/node/NodeStorageController.php

core/modules/node/lib/Drupal/node/Tests/NodeTypeTest.php

core/modules/node/node.admin.inc

core/modules/node/node.module

core/modules/node/node.pages.inc

core/modules/node/node.tokens.inc

core/modules/poll/lib/Drupal/poll/Tests/PollTestBase.php

core/modules/search/search.api.php

core/modules/system/system.api.php

core/modules/tracker/tracker.pages.inc