test: refactor test framework to use a rootfs skeleton

Instead of having to create files, and copying them in place for each
test, we move all static test files to a skeleton rootfs.  This makes
it a lot easier to get an overview of how things and how they work.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

test/tenv/start.sh

@@ -46,4 +46,4 @@ exec "$unshare"						\
      --mount						\
      --mount-proc					\
      --uts --ipc --net					\
-     "$chroot" "$TENV_ROOT" /bin/chrootsetup.sh "$@"
+     "$chroot" "$TENV_ROOT" /sbin/chrootsetup.sh "$@"