MFC r311925,r311968,r311969,r312008:

r311925:

Import testcase updates with code contributed back to NetBSD

This also (inadvertently) contains an update to
contrib/netbsd-tests/lib/libc/sys/t_wait.c (new testcases).

In collaboration with: christos@NetBSD.org

r311968:

Fix lib/libc/sys/access_test after r311925

sys/param.h needs to be #included in order for __FreeBSD_version to be checked

r311969:

Remove __HAVE_LONG_DOUBLE #define from t_strtod.c and place it in Makefile

This is to enable support in other testcases

Inspired by lib/msun/tests/Makefile .

r312008:

Upgrade NetBSD tests to 01.11.2017_23.20 snapshot

This contains some new testcases in /usr/tests/...:

- .../lib/libc
- .../lib/libthr
- .../lib/msun
- .../sys/kern

Tested on: amd64, i386