8024547: MaxMetaspaceSize should limit the committed memory used by the metaspaces Reviewed-by: brutisso, jmasa, coleenp

8003420: NPG: make new GC root for pd_set Summary: Move protection domain oops from system dictionary entries into a seperate set; the system dictionary references entries in that set now. This allows fast iteration during non-classunloading garbage collection. Implementation based on initial prototype from Ioi Lam (iklam). Reviewed-by: coleenp, iklam