This includes new TAP tests for a couple of areas not covered yet and
some improvements:
- More coverage for --no-ensure-shutdown, the enforced recovery step and
--dry-run.
- Failures with option combinations and basic option checks.
- Removal of a duplicated comment.

Author: Alexey Kondratov, Michael Paquier
Discussion: https://postgr.es/m/20191007010651.GD14532@paquier.xyz