Fix (skip) for some failing tests in a FreeBSD jail

[alvar-freude]

In FreeBSD Jails, the loopback interface usually has no IP address, but when using 127.0.0.1 then the local ip address is connected.

Some tests fail:

Running Build test
t/basic.t ... Failed 1/5 subtests 
t/simple.t .. 1/11 
#   Failed test 'loopback address'
#   at t/simple.t line 25.

#   Failed test 'loopback netmask'
#   at t/simple.t line 26.
# Looks like you failed 2 tests of 11.
t/simple.t .. Dubious, test returned 2 (wstat 512, 0x200)
Failed 2/11 subtests 
        (less 3 skipped subtests: 6 okay)

Test Summary Report
-------------------
t/basic.t (Wstat: 0 Tests: 5 Failed: 1)
  Failed test:  5
t/simple.t (Wstat: 512 Tests: 11 Failed: 2)
  Failed tests:  7-8
  Non-zero exit status: 2
Files=2, Tests=16,  1 wallclock secs ( 0.02 usr  0.01 sys +  0.09 cusr  0.04 csys =  0.16 CPU)
Result: FAIL
Failed 2/2 test programs. 3/16 subtests failed.
  LDS/IO-Interface-1.09.tar.gz
  ./Build test -- NOT OK

I fixed this by skipping the test in simple.t when the OS is FreeBSD and the test running inside a jail; in simple.t i fixed this by moving the failing test into the existing SKIP block.