Changes

Discarded bytes in Verbose GC

Report existing cummulative discarded bytes in allocation stats section
of VGC (reported as a part of GC-start increment).

At the present they are only TLH discards, although in theory there
could be small discards from non-TLH allocations when remainder is less
then min free entry, but we don't gather those stats. It's not
specifically reported as TLH ones, since in future we might add non-TLH
ones, too.

This is useful to report/check if TLH sizing is changed (via for example
tlhMaximumSize paramter), to see if there is any negative sideeffect
(increase of discards, which may potentially increase frequency of GCs).

Signed-off-by: Aleksandar Micic <Aleksandar_Micic@ca.ibm.com>
 (commit: 94a5279)