MFC r305358,r305449,r305451,r306367,r306397,r309474:

This also contains a merge of ^/projects/netbsd-tests-update-12@r304035 .
This change never hit ^/head because bin/cat's behavior was changed (on ^/head)
to match NetBSD.

PR: 210607

r305358:

Update contrib/netbsd-tests with new content from NetBSD

This updates the snapshot from 09/30/2014 to 08/11/2016

This brings in a number of new testcases from upstream, most
notably:

- bin/cat
- lib/libc
- lib/msun
- lib/libthr
- usr.bin/sort

lib/libc/tests/stdio/open_memstream_test.c was moved to
lib/libc/tests/stdio/open_memstream2_test.c to accomodate
the new open_memstream test from NetBSD.

Tested on: amd64 (VMware fusion VM; various bare metal platforms); i386 (VMware fusion VM); make tinderbox

r305449:

Install h_db to unbreak some of the lib/libc/db testcases after
r305358

r305451:

Fix lib/libc/rpc test assumptions added in r305358

- Require root in the tcp/udp subtests (it's needed on FreeBSD when
registering services).
- Skip the tests if service registration fails.

r306367 (by br):

Allow up to 6 arguments only on MIPS.

r306397 (by br):

Use right piece of code for FreeBSD.

r309474:

Don't build :strvis_locale if VIS_NOLOCALE is undefined

The copy of contrib/libc-vis on ^/stable/10 doesn't contain all of the features
in the ^/stable/11 // ^/head version, including VIS_NOLOCALE. The risk is lower
in conditionally running the test instead of backporting the newer version of
libc-vis