Changed PS-LOOP to emit DO* (i.e. normal JS for-loop code) rather than DO. It was...

Changed PS-LOOP to emit DO* (i.e. normal JS for-loop code) rather than DO. It was originally written when DO meant DO* (in today's terms). Using DO here makes the generated code slower and breaks a bunch of our existing cases. Also, DO* produces more idiomatic JS code and should be the default case (there is unfortunately no single default here that gives all the desired behavior, but this is a better tradeoff).