Why:
* The maintenance scripts in core are mostly untested and testing
them will help prevent regressions in the scripts.
What:
* Update Maintenance::maybeShowHelp to call ::fatalError instead
of directly calling die(). This is so that code which calls
this can be tested.
* Create GetConfigurationTest
Bug: T371167
Change-Id: Ifa31a3b759c2fdc1c869a3764b75515ec27a4648
