Giovanni Campagna authored Apr 21, 2013 and Philip Chimento committed May 09, 2018

Move handling of very special arguments (arrays, callback, caller
allocates) to the argcache virtual functions, and clean up
function invocations.
We now have three straight loops: marshal_in, marshal_out and
release. Some pointer arithmetics is introduced to ensure that
all indexes line up correctly.

FIXME: js_arg_pos can overrun js_out_argc sometimes when marshalling out

(Philip Chimento: rebased and fixed coding style.)