Add nsm-should-check IPv6 local subnet tests

* test/lisp/net/nsm-tests.el (nsm-check-local-subnet-ipv6): Now
that IPv6 addresses are returned from network-interface-list, test
nsm-should check and nsm-network-same-subnet for IPv6 as well.
1 job for master in 56 minutes and 16 seconds (queued for 3 seconds)
Status Job ID Name Coverage
failed #4387


Name Stage Failure
test-all Test
Makefile:319: recipe for target 'check-doit' failed
make[2]: *** [check-doit] Error 1
make[2]: Leaving directory '/builds/emacs/emacs/test'
Makefile:294: recipe for target 'check-expensive' failed
make[1]: *** [check-expensive] Error 2
make[1]: Leaving directory '/builds/emacs/emacs/test'
make: *** [check-expensive] Error 2
Makefile:959: recipe for target 'check-expensive' failed
ERROR: Job failed: exit code 1