MFC r279424,r279425,r279426,r279427,r279428,r279429,r279430,r279431,r279432:

r279424 (by rstone):

Tests of basic nvlist add functions

Differential Revision: https://reviews.freebsd.org/D1869
Reviewed by: jfv, pjd
Sponsored by: Sandvine Inc.

r279425 (by rstone):

Add tests for nvlist_clone

Differential Revision: https://reviews.freebsd.org/D1870
Reviewed by: pjd, jfv
Sponsored by: Sandvine Inc

r279426 (by rstone):

Add tests for nvlist_pack/unpack

Differential Revision: https://reviews.freebsd.org/D1871
Reviewed by: jfv, pjd
Sponsored by: Sandvine Inc.

r279427 (by rstone):

Add test cases for nvlist_move_*

Differential Revision: https://reviews.freebsd.org/D1872
Reviewed by: jfv, pjd
Sponsored by: Sandvine Inc.

r279428 (by rstone):

Add tests for nvlist_take_*

Differential Revision: https://reviews.freebsd.org/D1873
Reviewed by: jfv, pjd
Sponsored by: Sandvine Inc.

r279429 (by rstone):

Add tests for nvlist_free* functions

Differential Revision: https://reviews.freebsd.org/D1874
Reviewed by: jfv, pjd
Sponsored by: Sandvine Inc.

r279430 (by rstone):

Add tests for dnv_get_*

Differential Revision: https://reviews.freebsd.org/D1875
Reviewed by: jfv, pjd
Sponsored by: Sandvine Inc.

r279431 (by rstone):

Add tests for dnvlist_take_*

Differential Revision: https://reviews.freebsd.org/D1876
Reviewed by: jfv, pjd
Sponsored by: Sandvine Inc.

r279432 (by rstone):

Extend the unit test to fix the bug caught in r277925

Differential Revision: https://reviews.freebsd.org/D1888
MFC After: 1 month
Sponsored by: Sandvine Inc.