* ext/objspace/objspace.c: ObjectSpace.memsize_of(obj) returns
  with sizeof(RVALUE). [Bug #8984]
* gc.c (obj_memsize_of): ditto.
* NEWS: add a NEWS entry.
* test/objspace/test_objspace.rb: catch up this fix.
* test/ruby/test_file_exhaustive.rb: ditto.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48846 b2dd03c8-39d4-4d8f-98ff-823fe69b080e