MFC r292650,r292651:

r292650:

Move mac_bsdextended check up before running the test_libugidfw_strings testcases

I realize that these tests could be run before mac_bsdextended is loaded, but
it would overcomplicate things to special case handle the testcases before doing
the mac_bsdextended(4) feature check

The testcases will be split up so they can be run separately in the near future

r292651:

Delete the comment about running test_libugidfw_strings before testing
mac_is_present so it doesn't accidentally confuse people