Added evaluated argument to specialize method to allow later specializations to use it

This is in preparation for inlining methods in if and while specializations.

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Make invokable field in SendNodes to have a little nicer code.

Also give inlineable node in UnarySendNode a unique name, for inlining in if and while specializations.

Signed-off-by: Stefan Marr <git@stefan-marr.de>