Issue #2824851 by Wim Leers, arshadcn, amateescu, tedbow, timmillwood, Berdir, tstoeckler: EntityResource::patch() makes an incorrect assumption about entity keys, hence results in incorrect behavior

Issue #2827084 by damiankloip, Wim Leers, dawehner, prics, larowlan, catch, darrenwh: EntityNormalizer::denormalize should not throw UnexpectedValueException, but \Symfony\Component\HttpKernel\Exception\UnprocessableEntityHttpException, so we get a 422 response instead of 400

Issue #2813853 by Wim Leers: RequestHandler has its own error handling rather than leaving it to KernelEvents::EXCEPTION event subscribers

Issue #2824827 by damiankloip, dawehner, Wim Leers, klausi: \Drupal\hal\Normalizer\ContentEntityNormalizer::denormalize() fails with fatal PHP error when bundles are missing from link relation types

Issue #2737719 by Wim Leers, dawehner: EntityResource: Provide comprehensive test coverage: for every entity type, every format, every method

Revert "Issue #2737719 by Wim Leers, dawehner: EntityResource: Provide comprehensive test coverage: for every entity type, every format, every method"

This reverts commit 59781ffc.

Issue #2737719 by Wim Leers, dawehner: EntityResource: Provide comprehensive test coverage: for every entity type, every format, every method