Move database files to the new lib directory and update code accordingly.

core/includes/bootstrap.inc

core/includes/common.inc

core/includes/database/database.inc

core/includes/install.core.inc

core/includes/install.inc

core/includes/pager.inc

core/includes/registry.inc

core/includes/tablesort.inc

core/lib/Drupal/Core/Database/Connection.php

...ib/Drupal/Core/Database/ConnectionNotDefinedException.php

core/lib/Drupal/Core/Database/Database.php

core/lib/Drupal/Core/Database/Driver/mysql/Connection.php

core/lib/Drupal/Core/Database/Driver/mysql/Delete.php

core/lib/Drupal/Core/Database/Driver/mysql/Insert.php

core/lib/Drupal/Core/Database/Driver/mysql/Install/Tasks.php

core/lib/Drupal/Core/Database/Driver/mysql/Merge.php

core/lib/Drupal/Core/Database/Driver/mysql/Schema.php

core/lib/Drupal/Core/Database/Driver/mysql/Select.php

core/lib/Drupal/Core/Database/Driver/mysql/Transaction.php

core/lib/Drupal/Core/Database/Driver/mysql/Truncate.php