Issue #3377516 by longwave: Core subtree split is broken after adding branch alias

composer.json

composer.lock

composer/Metapackage/CoreRecommended/composer.json

composer/Metapackage/PinnedDevDependencies/composer.json

composer/Template/LegacyProject/composer.json

composer/Template/RecommendedProject/composer.json

core/composer.json

core/lib/Drupal.php

core/lib/Drupal/Component/Annotation/composer.json

core/lib/Drupal/Component/Datetime/composer.json

core/lib/Drupal/Component/Discovery/composer.json

core/lib/Drupal/Component/FrontMatter/composer.json

core/lib/Drupal/Component/Gettext/composer.json

core/lib/Drupal/Component/PhpStorage/composer.json

core/lib/Drupal/Component/Render/composer.json