>processVariables contains copy-paste code for optionalParameters and
>keywordParameters, so there's a need for a tiny helper function.
This patch adds the said helper. No test regressions. The patch looks a bit
funny, so it's not straightforward to count the line delta from the patch. It
still deletes more code than it adds.
Next patch will bring the merge of bindOptionalParameterDefaults and
bindKeywordParameterDefaults. Then I'll try removing unnecessary null
assignments from constructor, and then try avoiding array null checks
by ensuring that the arrays are always allocated. So, at the moment
it looks like the Closure.java saga will be at least 10 patches long
(and somehow I don't think that's the end of it).