Don't repeat any enterNode() implementation from FileReflector

When updating the location stack it's possible to just peek at the end of the appropriate array to get the class/function reflector. Hook parsing can also be done after the original enterNode() has a go since it only relies on the location stack.

Not only is this simpler than using LSEN from the context object (which would require making look ups into the arrays), but the LSEN part of the context object hasn't actually been implemented upstream yet.