Add way to properly parse JNDI urls in AS codebase

This is a followup of AS7-2138. Original code, in case no URL context threw NamingException. The AS7-2138 introduced a fallback to NamingContext in case AS7 does not provide custom hack for url( like EJB ). However the fallback did not fail with NamingException in case it did not locate Context. This essentially made it go knee deep into AS7 service lookups, which hides real cause of failure.