cron.rm_job and cron.rm_special do nothing (state cron.absent also broken)

Description of Issue

The cron module's features for removing cron jobs appears to be broken in salt 2019.2.1
Neither cron.rm_job nor cron.rm_special seems to do anything at all. They don't report any failure, but the don't remove the matching job either.

the cron.absent state also fails, always acting as if the cron job doesn't exist, when actually it does.

Setup

Plain default out-of-the-box salt 2019.2.1 on Debian 10

Steps to Reproduce Issue

Create a new cron job, this part will work...
``
`sudo salt "debian-salt-minion" cron.set_special jamesp '@hourly' 'date >> ~/crontest.log' identifier="TESTJOB"

Now try to delete it, this part will do nothing

sudo salt "debian-salt-minion" cron.rm_special jamesp '@hourly' 'date >> ~/crontest.log' identifier="TESTJOB"

The job will not be removed. You can verify with

sudo salt "debian-salt-minion" cron.ls jamesp

It doesn't matter if you use rm_job or rm_special
It doesn't matter if the job is for root or for some other user
It doesn't matter if you set an identifier or not

I have not been able to find any combination of arguments that can successfully remove any cron job

### Versions Report

Salt Version:
Salt: 2019.2.1

Dependency Versions:
cffi: Not Installed
cherrypy: Not Installed
dateutil: 2.7.3
docker-py: Not Installed
gitdb: 2.0.5
gitpython: 2.1.11
ioflo: Not Installed
Jinja2: 2.10
libgit2: 0.27.7
libnacl: Not Installed
M2Crypto: Not Installed
Mako: Not Installed
msgpack-pure: Not Installed
msgpack-python: 0.5.6
mysql-python: Not Installed
pycparser: 2.19
pycrypto: 2.6.1
pycryptodome: Not Installed
pygit2: 0.27.4
Python: 3.7.3 (default, Apr 3 2019, 05:39:12)
python-gnupg: Not Installed
PyYAML: 3.13
PyZMQ: 17.1.2
RAET: Not Installed
smmap: 2.0.5
timelib: Not Installed
Tornado: 4.5.3
ZMQ: 4.3.1

System Versions:
dist: debian 10.1
locale: UTF-8
machine: x86_64
release: 4.19.0-6-amd64
system: Linux
version: debian 10.1

Start by reproducing the documented cron.set_special, cron.rm_special, cron.rm_job, cron.absent, and cron.ls commands on Debian 10. Inspect the cron module entry points and their related tests, then verify that removal actually deletes the matching job and that cron.absent recognizes it before removal.