We don't usually do tests purely for one change, but one change was
special because when users will migrate to OVMF/AAVMF, commit 18f9f69b
makes their lives easier by allowing them to interleave <type/> inside
<os/>.  It would be nice of us to keep the possibility of them pasting
the loader and nvram elements wherever it is valid, hence this test.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>