Retrofit of mac_test regression and consistency test module for MAC

Retrofit of mac_test regression and consistency test module for MAC
Framework labels:

- Re-work the label state assertions to use a set of central
  ASSERT_type_LABEL() assertions.

- Test to make sure labels passed to externalize/internalize calls haven't
  been destroyed.

- For access control checks, assert the condition of all labels passed in.

- For life cycle events, assert the condition of all labels passed in.

- Add new entry point implementations for new MAC Framework entry points:
  mac_test_reflect_mbuf_icmp(), mac_test_reflect_mbuf_tcp(),
  mac_test_check_vnode_deleteextattr(), mac_test_check_vnode_listextattr().

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories