tests: Introduce 0043_concatenated_ranges_1 for subnets of different sizes

tests: Introduce 0043_concatenated_ranges_1 for subnets of different sizes

The report from https://bugzilla.netfilter.org/show_bug.cgi?id=1520
showed a display issue with particular IPv6 mask lengths in elements
of sets with concatenations. Make sure we cover insertion and listing
of different mask lengths in concatenated set elements for IPv4 and
IPv6.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>