Refactoring of *.test.mk

[Simon J. Gerraty]

Thanks Julio, will take a look.

We have made a number of changes internally to *.test.mk
so that it works well in our build env.

>You can find the relevant patches in:
>http://portal.meroh.net/~jmmv/freebsd-testing/ .
>
>The patches have been generated using quilt so take a look at the
>contents of the 'series' file to see in which order they would need to
>be applied.
>
>Each patch has a description at the top which can later be used as the
>commit log.