Merge branch '2951046-allow-parsing-php' into '11.x'

core/lib/Drupal/Component/Serialization/Yaml.php

core/lib/Drupal/Core/Config/AutoloadingStorage.php

core/lib/Drupal/Core/Config/ConfigInstaller.php

core/lib/Drupal/Core/Config/StorageComparer.php

..._test/config/install/config_backed_enum_test.settings.yml

...num_test/config/schema/config_backed_enum_test.schema.yml

.../config_backed_enum_test/config_backed_enum_test.info.yml

...fig/tests/config_backed_enum_test/src/BackedEnumValue.php

...ules/config/tests/src/Functional/ConfigInstallWebTest.php

...standard/config/install/field.storage.node.field_tags.yml

.../Drupal/Tests/Component/Serialization/BackedEnumValue.php

.../tests/Drupal/Tests/Component/Serialization/EnumValue.php

core/tests/Drupal/Tests/Component/Serialization/YamlTest.php