vm_node_stat must be used instead of vm_zone_stat. Unfortunately the
old code still compiles potentially leading to silent failure of
arc_evictable_memory()
AKAMAI: CR 3816601: Regression in zfs dropcache test
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Debabrata Banerjee <dbanerje@akamai.com>
Closes#6528