Jira 2326

CGIImpl.java already had a similar method named getCurrentURL()
which is called from
https://github.com/getrailo/railo/blob/4.1/railo-java/railo-core/src/railo/commons/pdf/PDFDocument.java#L428

IMO the new method is more accurate so maybe we should modify PDFDocument to
call the new method and remove the older getCurrentURL() method

also, I didn't add this to the dump keys (staticKeys) because I wasn't sure if we want that, but I can add it if you want.

https://issues.jboss.org/browse/RAILO-2326