The existing test used both `mergeArrays` and `checkListsMatch`. Those
were split, to make it a bit more clear what is being asserted.

Signed-off-by: Justin Kulikauskas <jkulikau@redhat.com>

Refs:
 - https://issues.redhat.com/browse/ACM-7889

Signed-off-by: Justin Kulikauskas <jkulikau@redhat.com>

Some of the logic in the `checkListsMatch` function does not require the
copies of the inputs to be created or sorted. This does those checks
first, potentially skipping the unnecessary work.

Signed-off-by: Justin Kulikauskas <jkulikau@redhat.com>

From some debugging for an issue, it became apparent that this function
was not actually being called in situations where it might have been
expected... Basically the switch case that might have called it is not
reachable.

Signed-off-by: Justin Kulikauskas <jkulikau@redhat.com>