#3015925 There is a new Theme extension object. system_region_list() and system_default_region() and region related constants are deprecated

from:
  fqn: 'fn:system_default_region'
to:
  fqn: '\Drupal\Core\Extension\Theme::getDefaultRegion'
from:
  fqn: '\Drupal\block\BlockRepositoryInterface::REGIONS_VISIBLE'
to:
  fqn: '\Drupal\Core\Extension\Theme::listVisibleRegions'
from:
  fqn: '\Drupal\block\BlockRepositoryInterface::REGIONS_ALL'
to:
  fqn: '\Drupal\Core\Extension\Theme::listAllRegions'
from:
  fqn: '\Drupal\block\Controller\BlockController::getVisibleRegionNames'
to:
  fqn: '\Drupal\Core\Extension\Theme::listVisibleRegions'
from:
  fqn: 'fn:system_region_list'
to:
  fqn: '\Drupal\Core\Extension\Theme::listAllRegions'
from:
  fqn: 'fn:system_region_list'
to:
  fqn: '\Drupal\Core\Extension\Theme::listVisibleRegions'
from:
  fqn: '\Drupal\block\BlockListBuilder::systemRegionList'
to:
  fqn: '\Drupal\Core\Extension\Theme::listAllRegions'
from:
  fqn: '\Drupal\block\BlockListBuilder::systemRegionList'
to:
  fqn: '\Drupal\Core\Extension\Theme::listVisibleRegions'