Revert "Issue #1986330 by subhojit777, marcelodornelas, wheatpenny, kasperg,...

Revert "Issue #1986330 by subhojit777, marcelodornelas, wheatpenny, kasperg, timaholt, stefank, AkshayKalose, develCuy, valthebald, moymilo, YesCT, dawehner, tstoeckler: When Batch ID doesn't exist, Drupal should emit a 404"

Somehow broke testbot/HEAD. Reverting for now.

This reverts commit 30432a03.