Send $foo."$bar"() calls through indy also.

Don't do much optimization here, this just simplifies code-gen and
brings it inline with that of normal method calls.
Remove now-unused code.
Update and simplify for loop code-gen.

It now desugars the calls through a QAST node, menaing we get rid of
the last use of building arg arrays and that such loops should now get
better code gen.
Remove more dead code.