Don't delegate to deprecated servlet APIs

[ifurnadjiev]

The following APIs have been deprecated since Servlet 2.x and removed in Servlet 6:

• ServletContextWrapper
  • getServlet(String)
  • getServlets(),
  • getServletNames(),
  • log(Exception, String)
• HttpSessionWrapper
  • getValue(String)
  • getValueNames()
  • putValue(String, Object)
  • removeValue(String)

There is no replacement for getSessionContext() as the complete class HttpSessionContext is deprecated. Keep it for now. For others use their replacement instead.