Infer correct values for tests automatically

Now tests compare the literal parser against the output of the
compiler. The little example contracts we are compiling for the
AACI already had the FATE value in them, in the form of the
instruction
	{'RETURNR', {immediate, FateValue}}
so we just extract that and use it for the tests.

src/hz_aaci.erl

@@ -22,8 +22,6 @@
          fate_to_erlang/2,
          erlang_args_to_fate/2,
          get_function_signature/2]).
-% Internal stuff that is useful for writing AACI unit tests.
--export([aaci_from_string/1, annotate_type/2]).
 
 %%% Types