Remove unnecessary finalize from JetRecTool

As mentioned in ATLASG-1544, tools like JetRecTool shouldn't have finalize() functions in the context of AnalysisBase. The code here wasn't necessary in any way; it just wrote out (and sometimes recorded to a text file) clock information to make it easier to track CPU usage, presumably for historical reasons. So here I've simply deleted it to avoid this issue. JetRecTool is in fact slated to become obsolete in the near future, so I can't imagine this removal can cause any problems.