FreeBSD doesn't support strings greater than MAXHOSTNAMELEN-1 in
{get,set}{domain,host}name. Adjust the tests to not exceed that
value when testing out the code

Add a positive and negative test for MAXHOSTNAMELEN-1 and
MAXHOSTNAMELEN, respectively

PR: 181127
In collaboration with: pho
Sponsored by: EMC / Isilon Storage Division