Let's try making WITH_TESTS more sane via NO_TESTS

This means that the code is now standardized and mostly localized to
bsd.own.mk; sprinkle around -DNO_TESTS in Makefile.inc1 in order to
enable test compilation only when needed (e.g. when `make everything`
is run).

Suggested-by: brooks
Signed-off-by: Garrett Cooper <yanegomi@gmail.com>