Issue #2125253 by tim.plunkett: Convert ()['redirect'] to ()['redirect_route()'].

core/lib/Drupal/Core/Form/FormBuilder.php

...s/aggregator/lib/Drupal/aggregator/FeedFormController.php

...gregator/lib/Drupal/aggregator/Form/CategoryAdminForm.php

...regator/lib/Drupal/aggregator/Form/CategoryDeleteForm.php

.../aggregator/lib/Drupal/aggregator/Form/FeedDeleteForm.php

...egator/lib/Drupal/aggregator/Form/FeedItemsRemoveForm.php

...les/aggregator/lib/Drupal/aggregator/Form/OpmlFeedAdd.php

core/modules/ban/lib/Drupal/ban/Form/BanAdmin.php

core/modules/ban/lib/Drupal/ban/Form/BanDelete.php

...ock/lib/Drupal/custom_block/CustomBlockFormController.php

...lib/Drupal/custom_block/CustomBlockTypeFormController.php

...ck/lib/Drupal/custom_block/Form/CustomBlockDeleteForm.php

...ib/Drupal/custom_block/Form/CustomBlockTypeDeleteForm.php

core/modules/block/lib/Drupal/block/BlockFormController.php

core/modules/block/lib/Drupal/block/Form/BlockDeleteForm.php

core/modules/book/book.pages.inc

core/modules/book/lib/Drupal/book/Form/BookOutlineForm.php

core/modules/comment/comment.admin.inc

...comment/lib/Drupal/comment/Form/ConfirmDeleteMultiple.php

...odules/config/lib/Drupal/config/Form/ConfigExportForm.php