RFR (S): 8012086: The object count event should only send events for instances occupying more than 0.5% of the heap

[Erik Helin]

Hi all,

this change makes sure that we only send the trace event 
vm/gc/detailed/object_count_after_gc if the total size of all the 
instances of a class occupies more than 0.5% of the used heap.

Webrev:
http://cr.openjdk.java.net/~ehelin/8012086/webrev.00/

Testing:
JPRT

Thanks,
Erik