The PrecertificateRevocation flag is turned on everywhere, so the
else case is unused code. This change updates the WFE to always
use the PrecertificateRevocation code path, and deprecates the old
feature flag.
The TestRevokeCertificateWithAuthz method was deleted because
it is redundant with TestRevokeCertificateWithAuthorizations.
Fixes#5240
Aaron Gable