RFR: 8234438: Remove some CMS leftovers

[Per Liden]

The following files has some CMS leftovers that can be removed. I'm sure 
there are more things like this here and there. I just happened to run 
across these while working on a different patch.

  src/hotspot/share/gc/shared/space.cpp
  src/hotspot/share/gc/shared/space.hpp
  src/hotspot/share/gc/shared/space.inline.hpp
  src/hotspot/share/memory/freeList.hpp
  src/hotspot/share/memory/iterator.hpp

Bug: https://bugs.openjdk.java.net/browse/JDK-8234438
Webrev: http://cr.openjdk.java.net/~pliden/8234438/webrev.0

/Per