Add per size class huge allocation statistics.

Add per size class huge allocation statistics, and normalize various
stats:
- Change the arenas.nlruns type from size_t to unsigned.
- Add the arenas.nhchunks and arenas.hchunks.<i>.size mallctl's.
- Replace the stats.arenas.<i>.bins.<j>.allocated mallctl with
  stats.arenas.<i>.bins.<j>.curregs .
- Add the stats.arenas.<i>.hchunks.<j>.nmalloc,
  stats.arenas.<i>.hchunks.<j>.ndalloc,
  stats.arenas.<i>.hchunks.<j>.nrequests, and
  stats.arenas.<i>.hchunks.<j>.curhchunks mallctl's.

include/jemalloc/internal/ctl.h

@@ -46,6 +46,7 @@ struct ctl_arena_stats_s {
 
 	malloc_bin_stats_t	bstats[NBINS];
 	malloc_large_stats_t	*lstats;	/* nlclasses elements. */
+	malloc_huge_stats_t	*hstats;	/* nhclasses elements. */
 };
 
 struct ctl_stats_s {