request for review (s) - 8005452: Create new flags for Metaspace resizing policy

[Jon Masamitsu]

8005452: Create new flags for Metaspace resizing policy

Previously the calculation of the metadata capacity at which
to do a GC (high water mark, HWM) to recover
unloaded classes used the MinHeapFreeRatio
and MaxHeapFreeRatio to decide on the next HWM.  That
generally left an excessive amount of unused capacity for
metadata.  This change adds specific flags for metadata
capacity with defaults more conservative in terms of
unused capacity.

Added an additional check for doing a GC before expanding
the metadata capacity.  Required adding a new parameter to
get_new_chunk().

Added some additional diagnostic prints.

http://cr.openjdk.java.net/~jmasa/8005452/webrev.00/

Thanks.