8144996: Replace the HeapRegionSetCount class with an uint
Reviewed-by: brutisso, jwilhelm

8137756: Remove hrs_err_msg and hrs_ext_msg from heapRegionSet
Reviewed-by: pliden, mgerdin

8080775: Better argument formatting for assert() and friends
Reviewed-by: kbarrett, pliden

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