8155634: Clean out old logging and dead code from SurvRateGroup
Reviewed-by: jmasa, tschatzl, sjohanss

8138750: Remove dead code in survivor rate group
Reviewed-by: mgerdin, tbenson

8137082: Factor out G1 prediction code from G1CollectorPolicy and clean up
Summary: Factor out G1 prediction code from G1CollectorPolicy into its own class, constify methods of G1CollectorPolicy and move more implementations to the cpp file.
Reviewed-by: jmasa, sangheki, ecaspole, kbarrett

8079792: GC directory structure cleanup
Reviewed-by: brutisso, stefank, david