v8: implement VirtualMemory class on SunOS
v8: implement VirtualMemory class on SunOS

Unbreaks build on SunOS. Re-applies 4908e5bf7a9c8014eefcf344e958bf0dad95d907.

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node