Add unit test coverage for _normalize_result

[kalikiana]

_normalize_result / update_result is lacking unit test coverage. This came up during code review. See openSUSE/qem-bot#154 (comment)

Relevant code:

qem-dashboard/lib/Dashboard/Model/Jobs.pm

Line 86 in 2d5dfec

my $normalized = _normalize_result($result);

[RaheelaTabassum]

please assign this issue to me @okurz

[okurz]

We are happy to receive pull requests for all contributors. No need to assign you to the issue.