Convert bin/sh over to ATF

The resulting diff from this thread: http://lists.freebsd.org/pipermail/freebsd-testing/2014-March/000271.html

Testing done:

<pre>
% rm -Rf /usr/tests/bin/sh
% cd /usr/src
% make hier
% cd bin/sh/tests
% make obj; make depend; make all; make install
% cd /usr/tests/bin/sh
% kyua test
</pre>

Example from kyua test:

<pre>
% kyua test
...
parser/functional_test:dollar____quote5__0  ->  passed  [0.203s]
parser/functional_test:dollar____quote6__0  ->  passed  [0.200s]
parser/functional_test:dollar____quote7__0  ->  passed  [0.193s]
parser/functional_test:dollar____quote8__0  ->  passed  [0.187s]
parser/functional_test:dollar____quote9__0  ->  passed  [0.198s]
parser/functional_test:empty____braces1__0  ->  passed  [0.192s]
parser/functional_test:empty____cmd1__0  ->  passed  [0.197s]
parser/functional_test:for1__0  ->  passed  [0.201s]
parser/functional_test:for2__0  ->  passed  [0.203s]
parser/functional_test:func1__0  ->  passed  [0.224s]
parser/functional_test:func2__0  ->  passed  [0.188s]
parser/functional_test:func3__0  ->  passed  [0.203s]
parser/functional_test:heredoc1__0  ->  passed  [0.212s]
parser/functional_test:heredoc10__0  ->  passed  [0.210s]
parser/functional_test:heredoc11__0  ->  passed  [0.208s]
parser/functional_test:heredoc2__0  ->  passed  [0.215s]
parser/functional_test:heredoc3__0  ->  passed  [0.246s]
parser/functional_test:heredoc4__0  ->  passed  [0.201s]
parser/functional_test:heredoc5__0  ->  passed  [0.230s]
parser/functional_test:heredoc6__0  ->  passed  [0.198s]
parser/functional_test:heredoc7__0  ->  passed  [0.199s]
parser/functional_test:heredoc8__0  ->  passed  [0.191s]
parser/functional_test:heredoc9__0  ->  passed  [0.211s]
parser/functional_test:no____space1__0  ->  passed  [0.212s]
parser/functional_test:no____space2__0  ->  passed  [0.191s]
parser/functional_test:only____redir1__0  ->  passed  [0.202s]
parser/functional_test:only____redir2__0  ->  passed  [0.193s]
parser/functional_test:only____redir3__0  ->  passed  [0.246s]
parser/functional_test:only____redir4__0  ->  passed  [0.279s]
parser/functional_test:pipe____not1__0  ->  passed  [0.192s]
parser/functional_test:var____assign1__0  ->  passed  [0.255s]
set-e/functional_test:and1__0  ->  passed  [0.150s]
set-e/functional_test:and2__1  ->  passed  [0.191s]
set-e/functional_test:and3__0  ->  passed  [0.171s]
set-e/functional_test:and4__0  ->  passed  [0.180s]
set-e/functional_test:background1__0  ->  passed  [0.186s]
set-e/functional_test:cmd1__0  ->  passed  [0.147s]
set-e/functional_test:cmd2__1  ->  passed  [0.184s]
set-e/functional_test:elif1__0  ->  passed  [0.224s]
set-e/functional_test:elif2__0  ->  passed  [0.180s]
set-e/functional_test:eval1__0  ->  passed  [0.129s]
set-e/functional_test:eval2__1  ->  passed  [0.139s]
set-e/functional_test:for1__0  ->  passed  [0.131s]
set-e/functional_test:func1__0  ->  passed  [0.147s]
set-e/functional_test:func2__1  ->  passed  [0.295s]
set-e/functional_test:if1__0  ->  passed  [0.145s]
set-e/functional_test:if2__0  ->  passed  [0.139s]
set-e/functional_test:if3__0  ->  passed  [0.140s]
set-e/functional_test:not1__0  ->  passed  [0.203s]
set-e/functional_test:not2__0  ->  passed  [0.169s]
set-e/functional_test:or1__0  ->  passed  [0.134s]
set-e/functional_test:or2__0  ->  passed  [0.139s]
set-e/functional_test:or3__1  ->  passed  [0.145s]
set-e/functional_test:pipe1__1  ->  passed  [0.183s]
set-e/functional_test:pipe2__0  ->  passed  [0.175s]
set-e/functional_test:return1__0  ->  passed  [0.158s]
set-e/functional_test:semi1__1  ->  passed  [0.198s]
set-e/functional_test:semi2__1  ->  passed  [0.172s]
set-e/functional_test:subshell1__0  ->  passed  [0.145s]
set-e/functional_test:subshell2__1  ->  passed  [0.179s]
set-e/functional_test:until1__0  ->  passed  [0.175s]
set-e/functional_test:until2__0  ->  passed  [0.153s]
set-e/functional_test:until3__0  ->  passed  [0.134s]
set-e/functional_test:while1__0  ->  passed  [0.146s]
set-e/functional_test:while2__0  ->  passed  [0.146s]
set-e/functional_test:while3__0  ->  passed  [0.153s]

380/380 passed (0 failed)
Committed action 12
%</pre>

DO NOT MERGE THIS INTO master AS IT IS PRISTINE!!